The DocBook community has developed several variants that, while not part of the normative specification, have proven to be useful. These include:
Simplified DocBook is a proper subset of DocBook. Therefore, any valid instance will also be valid against the full DocBook schema. The objective is to provide a significantly smaller schema that is useful for articles and other small documents. As of the publication of this book, the latest version of Simplified DocBook was based on DocBook V4.5. Further information can be found at http://www.docbook.org/schemas/simplified.
The DocBook website schema is a customization of the schema designed for building websites. There is also support in the DocBook stylesheets for this schema. As of the publication of this book, there is a version of the schema based on DocBook V5.0 under development. Information about the DocBook website and how to use it can be found in DocBook XSL: The Complete Guide [Stayton07] and at http://www.dpawson.co.uk/docbook/website/. The latter has information about the DocBook V5.0 version of the schema.
This schema is a customization for making slide sets. The schema and stylesheets can be found at http://docbook.sourceforge.net as part of the open source DocBook stylesheet distribution.