Architectural specification : Architectural Specification: Base : Configuration, specialization, and constraints : Specialization : Specialization module coding requirements : DTD syntax specialization module coding requirements
   
DTD syntax specialization module coding requirements
 
General element type declaration coding requirements
Structural module coding requirements
Topic type module coding requirements
Element domain module coding requirements
Attribute domain module coding requirements
To be extensible and backward compatible, DITA requires that a DTD implementation of structural and domain specialization modules conform to well-defined implementation (coding) requirements.
These coding requirements implement the specialization architecture with the capabilities and within the limitations of the DTD grammar. They are the coding requirements for structural specializations, element domain specializations, and attribute domain specializations.