Rajeev Agrawal C.-H. Wu William I. Grosky Farshad Fotouhi Diffusion maps-based image clustering. 9 2006 IWRIDL http://doi.acm.org/10.1145/1364742.1364754 conf/iwridl/2006 db/conf/iwridl/iwridl2006.html#AgrawalWGF06