Stefan Miltchev Jonathan M. Smith Vassilis Prevelakis Angelos D. Keromytis Sotiris Ioannidis 2008 40 ACM Comput. Surv. 3 http://doi.acm.org/10.1145/1380584.1380588 db/journals/csur/csur40.html#MiltchevSPKI08