1. XQuery 1.0: An XML Query Language, W3C Working Draft (April 4, 2005),
http://www.w3.org/TR/2005/WD-xquery-20050404/
2. XQuery 1.0 and XPath 2.0 Data Model, W3C Working Draft (April 4, 2005),
http://www.w3.org/TR/2005/WD-xpath-datamodel-20050404/
3. XQuery 1.0 and XPath 2.0 Functions and Operators, W3C Working Draft (April 4, 2005),
http://www.w3.org/TR/2005/WD-xpath-functions-20050404/
4. Lecture Notes in Computer Science;M.F. Fernandez,2003
5. Grinev, M.: XQuery Optimization Based on Rewriting (2003), Available at
http://www.ispras.ru/~grinev