S. Ahern, M. Naaman, R. Nair, and J. Yang, World explorer, Proceedings of the 2007 conference on Digital libraries , JCDL '07, 2007.
DOI : 10.1145/1255175.1255177

D. J. Crandall, L. Backstrom, D. Huttenlocher, and J. Kleinberg, Mapping the world's photos, Proceedings of the 18th international conference on World wide web, WWW '09, 2009.
DOI : 10.1145/1526709.1526812

D. Liu, X. Hua, L. Yang, M. Wang, and H. Zhang, Tag ranking, Proceedings of the 18th international conference on World wide web, WWW '09, 2009.
DOI : 10.1145/1526709.1526757

W. Wang, J. Yang, and R. Muntz, STING : A statistical information grid approach to spatial data mining, VLDB, 1997.