Subsetting and Customizing DITA
http://www.publishingsmarter.com/pages/teach/subset_dita/SubsetDITA_4000.html

Aschwanden, Bernard
Publishing Smarter
2006

Abstract:

This article explores ideas related to subsetting and customizing the DITA specification without the addition of new elements. Instead, we explore taking default rules and adapting them to meet the needs of specific writing and publishing environments. Introductory information about the DITA specification and the difference between subsetting and specialization is provided.