Yannis S. Avrithis Yannis Kalantidis Giorgos Tolias Evaggelos Spyrou Retrieving landmark and non-landmark images from community photo collections. 153-162 2010 ACM Multimedia http://doi.acm.org/10.1145/1873951.1873973 conf/mm/2010 db/conf/mm/mm2010.html#AvrithisKTS10