M. Liu, R. Cai, M. Zhang, und L. Zhang. Proceedings of the 20th ACM international conference on Information and knowledge management, Seite 87--92. New York, NY, USA, ACM, (2011)
B. Bahmani, R. Kumar, M. Mahdian, und E. Upfal. Proceedings of the 18th ACM SIGKDD international conference on Knowledge discovery and data mining, Seite 24--32. New York, NY, USA, ACM, (2012)