RELAX NG site http://www.relaxng.org/ RELAX NG is an easy to use Schema language RELAX NG Compact Spec http://relaxng.org/compact-20021121.html This specification discusses the compact syntax... RELAX NG's Compact Syntax http://www.xml.com/pub/a/2002/06/19/rng-compact.html Michael Fitzgerald's article on RELAX NG