1. Spam archive.
http://untroubled.org/spam/
2. Anderson, D., Fleizach, C., Savage, S., Voelker, G.: Spamscatter: Characterizing internet scam hosting infrastructure. In: Proceedings of 16th USENIX Security Symposium (2007)
3. Lecture Notes in Computer Science;P Andritsos,2004
4. Bezdek, J., Pal, N.: Cluster validation with generalized dunn’s indices. In: Proceedings of Second New Zealand International Two-Stream Conference on Artificial Neural Networks and Expert Systems, pp. 190–193 (1995)
5. Blanzieri, E., Bryl, A.: A survey of learning-based techniques of email spam filtering. Artif. Intell. Rev. 29(1), 63–92 (2008)