Panos Kalnis Gabriel Ghinita Kyriakos Mouratidis Dimitris Papadias Preventing Location-Based Identity Inference in Anonymous Spatial Queries. 1719-1733 2007 19 IEEE Trans. Knowl. Data Eng. 12 http://dx.doi.org/10.1109/TKDE.2007.190662 db/journals/tkde/tkde19.html#KalnisGMP07