Haifeng Yu Chenwei Shi Michael Kaminsky Phillip B. Gibbons Feng Xiao DSybil: Optimal Sybil-Resistance for Recommendation Systems. 283-298 2009 IEEE Symposium on Security and Privacy http://dx.doi.org/10.1109/SP.2009.26 conf/sp/2009 db/conf/sp/sp2009.html#YuSKGX09