R. Jäschke, A. Hotho, F. Mitzlaff, и G. Stumme. Recommender Systems for the Social Web, том 32 из Intelligent Systems Reference Library, Springer, Berlin/Heidelberg, (2012)
J. Yamagishi, T. Nose, H. Zen, T. Toda, и K. Tokuda. Proceedings of the 2008 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), стр. 3957-3960. Las Vegas, NV, USA, (марта 2008)