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