Chris Kanich Kirill Levchenko Brandon Enright Geoffrey M. Voelker Stefan Savage The Heisenbot Uncertainty Problem: Challenges in Separating Bots from Chaff. 2008 LEET http://www.usenix.org/events/leet08/tech/full_papers/kanich/kanich.pdf conf/nsdi/2008leet db/conf/nsdi/leet2008.html#KanichLEVS08