DocBook Wiki: wiki.docbook.org/topic/DocBookCssStylesheets
Badgers-in-foil: www.badgers-in-foil.co.uk/projects/docbook-css
tidy: www.w3.org/People/Raggett/tidy
m4: www.gnu.org/software/m4/manual/m4.html
Linux Documentation Project Author's Guide: www.tldp.org/authors
Sample Article Template: www.tldp.org/authors/template/Sample-HOWTO.xml
“DocBook Demystification HOWTO” by Eric Raymond: www.faqs.org/docs/Linux-HOWTO/DocBook-Demystification-HOWTO.html
“Take My Advice: Don't Learn XML” by Michael Smith: www.oreillynet.com/pub/a/oreilly/xml/news/dontlearn_0701.html
DocBook: The Definitive Guide by Norman Walsh and Leonard Muellner: www.docbook.org/tdg/en/html/docbook.html