P. Symeonidis, A. Nanopoulos, и Y. Manolopoulos. RecSys '08: Proceedings of the 2008 ACM conference on Recommender systems, стр. 43--50. New York, NY, USA, ACM, (2008)
R. Agrawal, T. Imieli&\#324;ski, и A. Swami. SIGMOD '93: Proceedings of the 1993 ACM SIGMOD international conference on Management of data, стр. 207--216. New York, NY, USA, ACM Press, (1993)