Harlan Hile Ramakrishna Vedantham Gregory Cuellar Alan L. Liu Natasha Gelfand Radek Grzeszczuk Gaetano Borriello Landmark-based pedestrian navigation from collections of geotagged photos. 145-152 2008 MUM http://doi.acm.org/10.1145/1543137.1543167 conf/mum/2008 db/conf/mum/mum2008.html#HileVCLGGB08