R. Salakhutdinov, A. Mnih, and G. Hinton. Proceedings of the 24th International Conference on Machine Learning, Corvallis, OR, International Conference on Machine Learning, (2007)
A. Barabasi, Z. Dezso, E. Ravasz, S. Yook, and Z. Oltvai. On Barabasi's personal website (http://www.nd.edu/~alb/html/publications.html) from Modeling of Complex Systems: Seventh Granada Lectures, (2002)