Anna Sperotto Gert Vliek Ramin Sadre Aiko Pras Detecting Spam at the Network Level. 208-216 2009 EUNICE https://doi.org/10.1007/978-3-642-03700-9_22 conf/ifip6-6/2009 db/conf/ifip6-6/eunice2009.html#SperottoVSP09