http://imil.net/docs/BSD-Makefile.txt

man pcreapi

man pcresample

pcredemo.c

http://tldp.org/HOWTO/Program-Library-HOWTO/more-examples.html

http://www.mentby.com/Group/openbsd-misc/pf-pfctl-and-parsey.html

http://ds9a.nl/lex-yacc/#download