ATA 2100 Specification
The key SGML standard for SKYDOC
Specifies 14+ DTDs for Air Transport Industry (ATI) technical information (AMM, AIPC, SB, etc)
Media Specification (Chapter 4) for packaging SGML documents for electronic delivery
TechReq (Chapter 3) describes how document suppliers and receivers should handle such constructs as revision control, effectivity, and using the common element and attribute definitions