P. Newson, and J. Krumm. Proceedings of the 17th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems, page 336--343. New York, NY, USA, ACM, (2009)
R. Gao, M. Zhao, T. Ye, F. Ye, Y. Wang, K. Bian, T. Wang, and X. Li. Proceedings of the 20th Annual International Conference on Mobile Computing and Networking, page 249--260. New York, NY, USA, ACM, (2014)
M. Alzantot, and M. Youssef. Proceedings of the 20th International Conference on Advances in Geographic Information Systems, page 99--108. New York, NY, USA, ACM, (2012)