Wei-Shinn Ku Ling Hu Cyrus Shahabi Haixun Wang Query Integrity Assurance of Location-Based Services Accessing Outsourced Spatial Databases. 80-97 2009 SSTD http://dx.doi.org/10.1007/978-3-642-02982-0_8 conf/ssd/2009 db/conf/ssd/sstd2009.html#KuHSW09