3.8 Further Reading
For more information about XPath 1.0, see the W3C Recommendation at http://www.w3.org/TR/xpath. The book Essential XML Quick Reference: A Programmer's Reference to XML, XPath, XSLT, XML Schema, SOAP, and More by Aaron Skonnard and Martin Gudginis also a good XPath reference.
A brief history of Unix, including the advent of paths, appears in the article “The Evolution of the Unix Time-sharing System” by Dennis Ritchie. This article has been published in several computer science publications, and is also available online at http://cm.bell-labs.com/cm/cs/who/dmr/hist.html.