A. Java, X. Song, T. Finin, и B. Tseng. Proceedings of the 9th WebKDD and 1st SNA-KDD 2007 workshop on Web mining and social network analysis, стр. 56--65. ACM, (2007)
S. Afonin. (2010)cite arxiv:1004.3142
Comment: 6 pages, paper contribution to "Excited QCD 2010", to be published in
Acta Phys. Pol. B (Proc. Suppl.).