Explain the Emergence of Markup Languages.

As the Web community grows and its members diversify in their abilities and skills, it is crucial that the underlying technologies be appropriate to their specific needs. HTML has been designed to make Web pages more accessible to those with physical limitations. HTML 4.0 developments inspired by concerns for accessibility include:

• Better tables, including captions, column groups, and mechanisms to facilitate non-visual rendering.
• A new client-side image map mechanism (the MAP element) that allows authors to integrate image and text links.
• Long descriptions of tables, images, frames, etc.
• Better distinction between document structure and presentation, thus encouraging the use of style sheets instead of HTML presentation elements and attributes.
• Better forms, including the addition of access keys, the ability to group form controls semantically, the ability to group select options semantically, and active labels.
• The ability to mark-up a text description of an included object (with the OBJECT element).
• The requirements that alternate text accompany images included with the IMG element and image maps included with the AREA element.
• Support for the ABBR and ACRONYM elements.

Authors who design pages with accessibility issues in mind will not only receive the blessings of the accessibility community, but will benefit in other ways as well: well-designed HTML documents that distinguish structure and presentation will adapt more easily to new technologies.

Advantages and disadvantages of using HTML

HTML is an easy to use and flexible alternative to traditional presentation and hyper stack software for the preparation of instructional material. HTML was designed originally to allow the rapid sharing of scholarly information, as a supplement to the scholarly journal. It was designed for people who did not have budgets that allowed them to hire programmers, so it was so simple that anyone could create and maintain it. It is a kind of software, which has been called world-ware.

The main advantages of HTML are its simplicity, portability and the ease with which thoughts are linked. HTML is simple because it has a fixed set of simple commands, which makes them easy to learn. HTML is portable because it is not proprietary; it can be used with different software. Although there are slight differences, HTML is displayed in the same way using any browser. This is because the fixed sets of tags are written right into the browser. (Lander, 1997).

Linking is the main advantage of HTML.  SGML can only link within a document. HTML goes beyond that with hypertext linking where it can link to places within a document but also to other documents. Hypertext linking is both flexible and powerful.

Another advantage to HTML is that it scales well. You can make a single HTML document and put it on one computer where it can be read.  You can also hand out diskettes with it for people to read on their own computers or you can put it onto a network server, all without changing a single word of the text. The same document serves on reader, a whole class or the entire world.

There are certain advantages to the Web, such as multimedia, interactivity, timeliness, and a certain air of "tech awareness" that make creating HTML pages something of a necessity for businesses and a good idea for families, too. There are disadvantages as well, including the cost in time and money, the learning curve for Web design, and the constant need to update.

Disadvantages

HTML has already shown its disadvantages. The main disadvantage of HTML is its limited tag set. Although this is an advantage in terms of simplicity and learnability, it is a disadvantage because there is a limited amount of things you can do with HTML, especially in terms of formatting. Even though Netscape and Internet Explorer have routinely added new tags, there are never enough tags to satisfy everyone. Web designers are always looking for more.

HTML's limitations also show up when you are trying to maintain your web page. Making a change in one area inevitably leads to something not working in another area. Links are continually moving and global changes are extremely difficult to do. "To change something, you change everything." (Rees, 1997, Paragraph 15).

HTML attempts to add functionality to Web pages by either downloading plug-ins or by using Java. The problem with downloading plug-ins is that they bring back proprietary software. Java is also limiting because it is difficult to learn and will not work on older browsers. (Dougherty, 1997).

6. XML

The Extensible Mark-up Language is a recommendation by the World Wide Web Consortium (W3C) for how to represent structured information in a text-based document. XML is a structured text document, no more or any less. Of course, it’s not the document itself that matters, but what can be done with it.

XML is a mark-up language whose roots originate in earlier efforts – a direct descendant of the Standard Generalised Mark-up Language (SGML) and cousin of the widely accepted and popular hypertext Mark-up Language (HTML) that currently powers the interface of most web sites.  As a mark-up language, it consists of "elements" encapsulated within angle brackets. These elements supply "metadata" or meaning for the content that is being marked-up. Elements can occur in pairs. When they do, the elements contain the same name reference, but the latter element is prefixed by a slash to indicate that it is the terminal element of the pair. The information between the pair of tags is the "content" that is being marked-up. That is pretty much all that there is to the simple definition of XML. Of course, this means that the elements can be named however you wish, but their meaning is very much specific to the needs of the developer or user.

So far we explained what is XML is now I will also mention some of the most frequently discussed advantages and disadvantages in using and implementing XML.

Advantages: XML is a structured text format 

The nature of XML is that it is a structured document format, in that it represents not only the information to be exchanged, but also the metadata encapsulating it’s meaning, and the structure of the information to be exchanged. Most information has structure of some type.  For example, information about a book in turn contains information about the title, author, chapters, body text, and index.  In turn, body text contains paragraphs, line text, footnotes, etc.  This information is therefore structured in that a document that describes a book needs to describe that information in a way that a person or machine can understand it.  Author information should not be contained within the index section, and vice-versa.

Most text files simply cannot offer this clear advantage.  They either represent simply the information to be exchanged without metadata, or include metadata in a flat, one-level manner.  Common file exchange formats such as comma- or tab-delimited text files merely contain data in predefined locations or delimitation’s in the file.  More complex file formats such as Microsoft Excel contain more structured information, but are machine-readable only and still do not contain the level of structuring present in XML.

Relational and object-oriented databases and formats do present similar advantages as XML, but for the most part, their formats are not text based. Formerly, to get the advantage of a structured format a binary (or machine-readable only) format was employed.  Surely, there are other text-based formats that include metadata regarding information and are structured in a hierarchical representation, but they have not caught on in popularity nearly to the extent that XML or even SGML has.

However, all the added value in representing data and metadata in a structured manner, some projects simply do not require the complexity that XML introduces.  In these cases, simple text files do the job more efficiently.  For example, a configuration file that includes a short list of a few commands and their values does not require a multi level, metadata-enhanced file format for its communication.  Therefore, one should not take the stance that simply because XML contains structure and metadata it should be used for all file formatting and document exchange needs.

While XML does offer validation technology, it is not currently as sophisticated as many of the EDI syntax checkers.  XML editors often lack the detail and helpfulness found in common EDI editors.  Many EDI syntax editors can report error details throughout a document, and can complete parsing of the entire document.  Many XML editors are unable to proceed beyond the first syntax.

Advantages: There are an increasing number of individuals with XML skills

Due to XML’s popularity, ease of use, and increasing proliferation of tools, the number of individuals and organisations skilled in XML use is increasing exponentially.  It is becoming considerably easier to find skilled employees and contractors that are familiar with XML, the standards, and best practices for implementing XML in multiple environments.

This proliferation of trained resources is a direct result of XML's open and standard nature.  XML training is becoming standardised, since companies can hire individuals who are trained in the open standards versus familiarity with specific products or versions of those products.  The number of training resources such as books, online training, in-person training, developer web sites, conferences, seminars, and additional means of gaining information on XML is also increasing.  With such a quantity of people walking around with XML in their heads, there is no doubt that XML will continue to have a bright future.

While getting employees and resources that are XML familiar may be increasingly easier, their familiarity with common business processes and the pitfalls that e-Commerce and e-Business efforts entail may be lacking.  A side effect of the rapid growth of the Internet generation of practitioners is that many are self-taught, and have primarily HTML and Java programming skills to the exception of others.  Most of these individuals usually have not had formal exposure to data fundamentals in general and the relational model in particular.  The rapid emergence of "green" XML developers may in essence be a setback for some that may depend on developers with the knowledge to not repeat errors made years earlier in other efforts, such as EDI.  It may not always be sufficient to find "XML experts", but to also find "business process experts" that are familiar with XML.  Hopefully, these too will be easier to find in the near future.

Disadvantages: XML is license-free, platform-neutral, and widely supported 

As mentioned earlier, XML is a technology that has no single owner or point of commercial licensing. As such, it can be freely implemented in any application or usage scenario that an organisation sees fit without incurring licensing costs. Due to its separation of process from content, it is also a good example of a platform-neutral data format. See earlier discussion on the separation of process from content for a more thorough discussion of how this benefits the ability to exchange data on disparate platforms.

In addition, XML is widely supported by individuals and organisations of all sorts. As a truly open-source and open-process technology, XML provides implementers a wide base of resources that can provide assistance in its implementation. Rather than being constricted to getting technical support and assistance from a single company, XML provides implementers the opportunity to obtain an XML-based product from one company, implementation services from a second company, and support and ongoing maintenance from yet another company.  This is the essence of the open-source movement.

Even though XML is in itself a license-free, platform-neutral, and widely supported technology base, applications and other technologies built using XML are not guaranteed to contain similar qualities.  Many companies will be apt to make use of XML to create commercial, proprietary, and less-supported products.  Companies should beware claims that because XML is open, so too will be all applications that are built with it.

XML can be likened to ASCII text files.  ASCII text files are also license-free, platform-neutral, and widely supported file formats, but many companies have developed text-based file formats that are proprietary in nature. It is not XML, but how uses it and licenses it that counts.

Disadvantages: XML can be viewed with simple tools such as browsers 

In the same vein as the argument regarding easily available and inexpensive XML processing tools, there also exist a number of low cost methods for visualising XML. These methods fall into one of three camps:

• Internet browsers natively viewing XML, or using XSL or CSS to render on the browser
• Conversion of XML to HTML at server-side, run-time or in batches using XSL or other methods
• Use of specialised Java applications to render in browser

The reasons for the visual display of XML documents are plentiful. There are many instances when viewing an XML document is necessary in one manner or another. These instances include the need to edit XML files, visual creation of XML documents, debugging, and human processing of XML files that "fall through the cracks" of automated systems.

In addition, there are an increasing number of visual tools for the creation, editing, debugging, and manipulation of XML documents are emerging. Many are low cost, if not free, and are very well suited to the tasks necessary in manipulating XML files. These tools not only allow a user to gain access to the "raw" XML document, but to gain a visual interpretation of the metadata in a graphical manner, allowing for navigation within XML files of a substantial size.

It is important not only to process and otherwise make use of XML documents, but also to make it easy to create, manipulate, and debug those very same documents. Fortunately, XML has provided a rich technology base from which doing so is low cost and sophisticated.

While it is possible to use browsers as a freely available XML visualisation tool, browser support for XML is currently spotty and not universal. However, the most appropriate question is who needs to view the XML data and why? If the XML information is meant to be machine produced and consumed, then the likelihood of a developer needing to poke their way into what may be unrecognisable XML code is low. More necessary are business applications that understand XML and can interpret the documents in a manner that is relevant to the context in which it was produced. After all, if a business user is entering a purchase order in a system, they will be unable to debug an XML document if the other party rejects it. Instead, the tool used to create the document will have to interpret the results and present them back to the user in a consumable manner.

So far, these business and context-sensitive tools have yet to appear. In general, the usability of XML is currently geared towards developers and programmers. Another evolution in XML is needed before the business-level public can generally consume it.

7. WML

Normal web-pages use HTML code to display information, however, phones and other mobile devices require another language i.e. WML (Wireless Markup Language) to display their Internet information.

WML is the only language available that is designed for creating applications that run on WAP phones. WML was preceded by an unpopular HDML (Handheld Device Markup Language), a product formalized by the company Unwired Planet (UP).

 

WML is a language based on XML, and is intended for use in specifying content and user interface for narrowband devices like mobile phones. WML is an XML application for mobile devices just as XHTML is an XML application for Web browsers. WML consists of the following WML is designed with the restrictions and constraints of small narrowband devices in mind. These includes:

• Small display and limited user input facilities.

• Narrowband network connection.

• Limited memory and computational resources.  

WML includes five major functional elements

1. Text presentation and layout - WML includes text and image support, including a variety of formatting and layout commands;

Layout and presentation is not one of WML weaknesses. It is very difficult to perform layout design when the number of WML-enabled devices and screen sizes are quite small. An Example of the structure of the WML Element is shown in figure 1 below:

The basic structure of a WML document looks like this:

<?xml version="1.0"?>

<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.3//EN"
"http://www.wapforum.org/DTD/wml13.dtd">

<wml>

  <head>

    [...]

  </head>

  <template>

    [...]

  </template>

  <card id="start" title="A WML App">

    [...]

  </card>

</wml>

Figure 1: Structure of the WML Element

(2) Inter-card navigation and linking - WML includes support for explicitly managing the navigation between cards and decks;

Cards can link to one another within a deck, or they can link to cards in other decks. By linking to a card in another deck, a separate fetch to the server (or cache) is required to retrieve the deck.

 (3) String parameterisation and state management - all WML decks can be parameterised, using a state model.

(4) Head Element

The head element in WML is similar to the <head> ... </head> in HTML, but it supports a very restricted subset of information. In general, the head element provides some access restriction and allows you to define meta tags.

(5) The Template Element

A template allows you to describe events. Events can be configured to handle the following:

Ontimer:

This action is called when a  has reached its preset time value.

Onenterforward:

This event action is called when a user navigates forward to the card (as if clicking a link in an HTML browser).

Onenterbackward:

This action occurs when a user agent navigates back to the card (as if clicking on the "back" button in an HTML browser)

Listed blow is number of other Event elements

Tasks                 Variables         User input

Go                 Sever                Input

Prep                                Select

Refresh                        Option

Snoop                                Opt group

                                Field set

Anchors, Images, and Timers

Anchor

Imp

Timer

WML Script is a scripting language that is very similar to JavaScript. However, rather than bedding WMLScript in the WML decks, WML contains only references to WMLScript URLs. Another difference is that WMLScript compilation units need to be compiled into the WMLScript byte code before it can be run on a WAP client (e.g. a WAP phone). Such a WAP browser (such as DSR's WAR browser) must contain a WMLScript Virtual Machine (VM) to run the compiled script.

Advantages and disadvantages of using WML

• WAP phones allow wireless access to the net.
• WML documents are designed to be compact and efficient on slow networks.
• The WML syntax itself is relatively easy to learn.
• Navigation in WML is quite similar to HTML concepts.
• WML Script a scripting is very similar to JavaScript.
• The WAP Forum has over 360 member companies.
• There are currently over a million, WML pages available,

().

Disadvantages

∙        Lack of layout features for pages, It is very difficult to perform layout design when screen sizes differ so widely. Mobile devices are “inconsistent in how they handle white space”)

• WAP phenomena   has struggled to live up to its forecasted popularity, the emergence of the 3G mobile devices is likely have an adverse effect on the future of WML.
• Many WAP enabled devices are quite slow in downloading pages.

The future of WML

In the year 2000 useit.com website conducted a field study of WAP users in London. After a week's experience using WAP, study participants had one resounding conclusion:

“70% of them said that they would not be using WAP in a year and that the services were poorly designed”

However, when one compares Useit.com 1994 study of the World Wide Web to the field study of WAP, it is evident to see very similar results to that of WAP. “When things got better in subsequent years (especially around 1997), many more users got onto the Web and commercial use exploded”. Therefore there is a possibility that mobility's evolution will follow that of the Web

8. SMIL

In 1998, The World Wide Web Consortium approved SMIL, Synchronized Multimedia Integration Language (pronounced "smile"), as the standard

markup language for interactive Streaming multimedia presentations.

SMIL (pronounced smile) stands for Synchronized Multimedia Integration Language. It is a markup language similar to HTML. SMIL includes specific tags and structures just as HTML does SML, however, differs from HTML, HTML is the language used for the layout of Web pages with text and graphics, SMIL is the language used to layout audio/video presentations using tools such as Real Player G2 and QuickTime 4.1, etc.

“Currently, the most widely used player is Real Networks Real Player. Real Player, with 95 million registered users in 1999, makes use of Real System G2 files, one of the best streaming media file formats. Apple has added support of SMIL to its QuickTime Player in version 4.1.’’ (Steven Drywall, 2001).

SMIL is designed to be easy to learn HTML like language. SMIL was created with specific objective of solving the problems of coordinating the display of a variety of multimedia (video, audio and graphics) on Web sites. “By using a single time line for all of the media on a page their display can be properly time coordinated and synchronized”.

A few examples   SMIL implementation

Interactive video

Using interactive video to create informational updates, for online training, educational broadcasts and other forms of interpersonal communications. Virtual meetings produced with SMIL and Streaming media is a real option.

Improved advertising

Rich-media enhanced advertising can create new and more effective means for advertisers to communicate with consumers attract potential customers and establish brand awareness. According to “April 1999 Millard Brown Interactive Study, in-stream advertising was found to increase brand impact significantly”.

Superior Content

Adding narration over scrolling text, or true video and animation-based content, is far more desirable to the consumer and more valuable than static text alone.

Advantages and Disadvantages of using SMIL

One of the greatest advantages of SMIL is that it requires only a simple text editor to write scripts keeping multimedia authoring as accessible as HTML.

• Time and control a presentation. The SMIL file lets you easily control

the presentation timeline. You can start an audio clip playing at 2.5

seconds into its internal timeline, for example, without changing the

encoded clip.

• Lay out a presentation. When your presentation includes multiple clips, such as a Real Video clip playing simultaneously with text captions or banner graphics; you use SMIL to define the layout.
• Provide alternate presentations SMIL can stream clips in multiple languages, or for different bandwidths.

Disadvantages

• There has not as yet been a final specification so SMIL files are not completely standardized across platforms.

• There is currently a lack of editors and development tools.

Overall, the Internet remains a competitive tool for maximising the use of wires. Many Companies that use the Web to sell products, inform customers, or promote services can benefit from using rich-media (through SMIL) on their Websites.

---

9. OTHER MARKUP LANGUAGES

There are other types of markup languages and we will only mention two languages as follows:

MathML

MathML is an XML application for describing mathematical notation and capturing both its structure and content. The aim of MathML is to enable mathematics to be served, received, and processed on the Web, just as HTML has enabled this functionality for text.

MathML is human-readable it is anticipated that, in all but the simplest cases, authors will use equation editors, conversion programs, and other specialized software tools to generate MathML. Several early versions of such MathML tools already exist, and a number of others, both freely available software and commercial products, are under development.

Although there is a price to be paid for the ambitious goals behind MathML - it is a verbose, complicated language not well suited to hand editing - the payoff in terms of power and versatility is quite impressive:

• More information about structure and meaning allows better conversion to other formats.
• More information allows better searching and indexing.
• Ability to encode expressions in a structured, media-independent way allows greater interoperability between wide ranges of software.
• Ability to encode meaning allows expressions to be evaluated as well as displayed in many cases.

Because of these advantages, many math and science software vendors have begun adding MathML support to their products, or are planning to add support soon. As a result, the now well-known "network effect" has already begun to boost the importance of MathML even further - once a critical mass of applications support MathML, the interoperability benefits start to outweigh the costs of conversion.

The advantages and disadvantages of using MathML

Advantages

• Can encode usage as well as appearance.
• XML is “taking over” document formatting.
• Allow web link math interface.
• An official W3C standard.
• Full hypertext support.
• Has support for computer algebra systems.
• Has support for visually impaired "viewers".
• Should produce relatively small, quick downloading files.

Disadvantages

• Will take special equation editors to create equations.

• Currently not supported by browsers.

• Browsers require plug-ins to render it.

• Verbose: lots of text to produce a little math.

CML

Chemical Markup Language (CML) is a radical new approach in to managing molecular information and provides a simple yet powerful way to manage a very wide range of problems with a single language. This language, derived from SGML, is formal, extensible, and already has a very wide range of tools to process it, since SGML is very widely used in many disciplines.

According to Peter Murray-Rust “CML does not cover all chemistry but concentrates on "molecules" (discrete entities representable by a formula and usually a connection table).”

CML supports the following,

• CML allows the definition of molecular structures within a document.

• The information can be transmitted to other applications.

∙        XML processors can pull out CML elements and pass these to applications that perform actions like preparing a printout of the information or creating an online three-dimensional model of the information.

CML has been used to manage documents and information in the following areas:

• Macromolecular Sequence.
• Macromolecular Structure.
• Spectra.
• Organic Molecules.
• Publishing.
• Quantum Chemistry.
• Inorganic Crystallography
  and others.

Where is it used?

Various different types of organisation have adopted, or are adopting CML. These organizations include Governmental and global agencies (e.g. drug regulatory agencies through the International (government). National Cancer Institute,

Developmental Therapeutics program (NCI/DTP).

Peter Murray-Rust's Chemical Markup Language [CML] is used for representing molecular and chemical information. Figure 2 below illustrates the CML document for a water molecule (H2O).

                                         <?xml version="1.0"?>

                                         <CML>

                                           <MOL TITLE="Water">

                                             <ATOMS>

                                               <ARRAY BUILTIN="ELSYM">H O H</ARRAY>

                                             </ATOMS>

                                             <BONDS>

                                               <ARRAY BUILTIN="ATID1">1 2</ARRAY>

                                               <ARRAY BUILTIN="ATID2">2 3</ARRAY>

                                               <ARRAY BUILTIN="ORDER">1 1</ARRAY>

                                             </BONDS>

                                           </MOL>

                                         </CML>

Figure 2:  Water Molecule in CML

According to Peter Rust Article on CML it is apparent to see that XML is still very new and not yet fixed, “but the CML has used an XML-like philosophy for many months and so there is no problem in making it follow the emerging 'standard'”.

But one can argue that this, however, is unlikely to affect the current version of CML documents, “other than possibly to add some additional boilerplate header information to help parsers. Remember that CML is still strict SGML so nothing has been lost in this simplification”.

     

After reading the FAQ of CML by Peter Murray-Rust, 1996-1997. The following advantages and disadvantages can be deduced

Advantages of using CML

• High capacities.
• Flexible slug count.
• 2 Slugcount change during production.
• Product flow on normal operation level.
• Small footprint.
• Pressure less infeed with buffer possible.
• Slug forming is done by all channels to ensure an accurate nominal weight per slug.
• Servo driven.
• Speed can be adjusted continuously and connected to the packaging machine speed.
• The CML can be connected to most types of packaging machines with a flight bar in feed.

Disadvantages of using CML

• It is not software, so it won't actively 'do' anything! The relevant question is "what information can CML not carry?"

• CML has no special support at present for: Chemical reactions.

• Queries, substructures, Mark up structures, libraries, etc. These all require a grammar, and there is no currently accepted grammar for chemistry.

• SGML is very good at providing the containment required in Object-Oriented systems, but not well suited to inheritance.

10. OVERALL CONCLUSION

We have successfully met the aim of the report, which was to explain and evaluate different types of markup languages. In summary:

• SGML is a Standard Generalized Markup Language defined in ISO Standard 8879:1986. It is the international standard way for creating descriptive markup languages.
• HTML (HyperText Markup Language) is the best-known mark-up language. HTML is the language of the Web.
• XML (The Extensible Mark-up Language) is a recommendation by the World Wide Web Consortium (W3C) for how to represent structured information in a text-based document.
• WML (Wireless Markup Language) is the only language available that is designed for creating applications that run on WAP phones.
• SMIL (Synchronized Multimedia Integration Language) is the standard markup language for interactive Streaming multimedia presentations.
• MathML (Mathematics Markup language) is an XML application for describing mathematical notation and capturing both its structure and content.
• CML (Chemical Markup Language) is a radical new approach in to managing molecular information.

11. REFERENCES

Background to Markup Languages and SGML

(1) LOU B., 1995, What is SGML and How Does It Help? [Online]. TEI working paper EDW25. Available at: URL  

[Accessed 22nd October 01].

(2) GEORGE D., 1999, English 569-Markup Languages and Hypertext-Fall 1999 [Online]. University of Washington. Available at: URL

[Accessed 22nd October 01].

(3) MARTIN B., 1992, An Introduction to the Standard Generalized Markup Language (SGML) [Online]. The SGML Centre. Available at: URL  [Accessed 25th October 01].

(4) SYD B., 1997, An Introduction to SGML [Online]. Available at: URL  [Accessed 25th October 01].

CML

(5) MURRAY-R. P., 1996-1997, FAQ [Online]. Available at: URL

[Accessed 24th October 01].

(6) MURRAY-R.P, 2001, Chemical Markup Language. A Position Paper [Online]. Available at: URL

[Accessed 24th October 01].

(7) COVE R., 2001, The XML Cover Pages Chemical Markup Language [Online]. Available at: URL

[Accessed19th October 2001].

WML

(8) GOWANS D., 1999, WML (Wireless Markup Language): An Introduction

[Online]. Available at: URL

[Accessed 9th October 2001].

(9) JAKOB N., 2000, WAP Field Study [Online]. Useit.com. Available at: URL

[Accessed 9th October 2001].

(10)  S., 2001, An introduction to WAP [Online]. Available at: URL

[Accessed 9th October 2001].

SMIL

(11) BROWN K., 1999, The Future of SMIL  [Online]. Available at: URL

 

[Accessed 15th October 2001].

(12) DRYWALL S., 2001, Confluent Technologies [Online]. Available at: URL

[Accessed 20th October 2001].

(13) DRYWALL S., 1999-2001, What is SMIL? [Online]. Confluent Technologies Inc. Available at: URL

[Accessed 20th October 2001].

HTML

(14) DOUGHERTY, D, 1997, Multidimensional files: There's a bright future beyond HTML. Web Review [on-line], Available at: URL  

[Accessed 24th October 2001].

XML

(15) LANDER, R, 1997, XML: The new markup wave. [Online]. Available at: URL  

[Accessed 19th October 2001].

(16) BOSAK, J, 1997, XML, Java and the future of the web [Online]. Available at: URL

[Accessed 19th October 2001].

(17) REES, L. C, 1997, What the XML - An introduction to XML. [Online]. Available at: URL  

[Accessed 19th October 2001].

MathML

(18) BOYE, J, 1998, MathML-What’s in it for us? [Online]. Available at: URL  

[Accessed 19th October 2001].

(19) W3 Organization Resources. Available at: URL

 [Accessed 10th October 2001].