XML Bible, Gold edition, Chapter 23
Elliotte Rusty Harold
Hungry Minds, 2001
ISBN 0-7645-4819-0
http://www.cafeconleche.org/books/biblegold/chapters/ch24.html
This presentation: http://www.cafeconleche.org/slides/xmlone/london2002/schemas
W3C Schema Primer: http://www.w3.org/TR/xmlschema-0/
XML Schema Part 1: Structures: http://www.w3.org/TR/xmlschema-1/
XML Schema Part 2: Datatypes: http://www.w3.org/TR/xmlschema-2/