In CTW, following the framework introduced in XWATL [Ogievetsky 1999a, 1999b], XSLT style sheets are divided into three layers:
The back-end or query layer. This layer is responsible for extracting required information from the topic map, assembling natural language generation constructs, and building syntax that aggregation and syndication software agents can understand.
The layout layer. This layer controls how HTML elements are arranged on the Web page or WML card. It calls presentation-layer templates to style content.
The presentation layer. This layer contains XSLT templates responsible for the particular look and feel of the Web pages or WML cards. Note that the presentation and layout layers can be altered to build other presentations ...