Path, Predicates, and XQuery
http://www.devarticles.com/c/a/XML/Paths-Predicates-and-XQuery/

Walmsley, Priscilla
Dev Articles
2008

Abstract:

In this conclusion to a three-part series on path expressions, you'll learn about complex predicates, dynamic paths, and more. This article is excerpted from chapter four of the book XQuery.