Zhang Fu Marina Papatriantafilou Philippas Tsigas Mitigating Distributed Denial of Service Attacks in Multiparty Applications in the Presence of Clock Drifts. 63-72 2008 SRDS http://dx.doi.org/10.1109/SRDS.2008.30 conf/srds/2008 db/conf/srds/srds2008.html#FuPT08