1. Monty python’s flying circus: final sketch of the 25th show, Available: http://en.wikipedia.org/wiki/Spam_%28Monty_Python%29
2. Bilca, M., Lo, J., Kerrest, F., Wytock, D.: The Ethics of SPAM, Available: http://cse.stanford.edu/classes/cs201/projects-97-98/spam/
3. Linden, P.: Re: first case of spam, Available: http://www.rahul.net/falk/jjspam.txt
4. Net. general, the dinette set heard round the world, Available: http://groups.google.com/groups?selm=3375%40drutx.UUCP
5. Lindberg, G.: Anti-Spam Recommendations for SMTP MTAs, RFC-2505 (February 1999)