Yu-Ling Hsueh Roger Zimmermann Wei-Shinn Ku Haojun Wang Chung-Dau Wang PLUS: A Message-Efficient Prototype for Location-Based Applications. 1515-1518 2009 ICDE http://dx.doi.org/10.1109/ICDE.2009.48 conf/icde/2009 db/conf/icde/icde2009.html#HsuehZKWW09