http://www.gnu.org

http://www.debian.org

http://www.linux.org

http://www.linux.com

http://www.linux.hr

http://gddistrowatch.tuwien.ac.at

http://www.postgresql.org

http://www.mojCD.com

ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO

http://www.doc.ic.ac.uk/~wjk/UnixIntro

http://emoglen.law.columbia.edu/publications/dcm.html