11.3 Further reading

Mastering Regular Expressions: by Jeffrey Friedl
3rd Edition (2006) O'Reilly.
Exhaustive treatment of regular expressions in all their various incarnations.
Regular Expression Pocket Reference: by Tony Stubblebine
2nd Edition (2007) O'Reilly.
Quick reference for regular expressions.
Regular-Expressions.info: http://www.regular-expressions.info
Comprehensive online resource.

Paul Murrell