1. Amir, A., Efrat, A., Myllymaki, J., Palaniappan, L., Wampler, K.: Buddy tracking - efficient proximity detection among mobile friends. Pervasive and Mobile Computing 3(5), 489–511 (2007)
2. Kalnis, P., Ghinita, G., Mouratidis, K., Papadias, D.: Preventing location-based identity inference in anonymous spatial queries. IEEE Transactions on Knowledge and Data Engineering 19(12), 1719–1733 (2007)
3. Lecture Notes in Artificial Intelligence;K. Liu,2006
4. Mascetti, S., Bettini, C., Freni, D., Wang, X.S.: Spatial generalization algorithms for LBS privacy preservation. Journal of Location Based Services 2(1), 179–207 (2008)
5. Mascetti, S., Bettini, C., Freni, D., Wang, X.S., Jajodia, S.: Privacy-aware proximity based services. In: Proc. of the 10th International Conference on Mobile Data Management, pp. 31–40. IEEE Computer Society, Los Alamitos (2009)