Need an XML Query Engine Java Bean? Howard Katz has developed one that is free for personal use. It supports XQL syntax for querying.

A Java based storage and query application for large XML documents. The functionality may be accessed via command line invocation or the Java API. The engine consists of two main parts: A persistent implementation of the W3C-DOM, and a full implementation of the XQL language

A Frequently Asked Questions list for the XML Query Language. This FAQ and the associated XQL Mailing List are intended to point you to resources that will help you learn, use, or implement XQL.

A discussion on why XML repositories should be XQL enabled in the context of C-Web.

This paper identifies essential features of an XML query language by examining four existing query languages: XML-QL, YTL, Lorel, and XQL