Hua Lu Zhiyong Huang Christian S. Jensen Linhao Xu Distributed, Concurrent Range Monitoring of Spatial-Network Constrained Mobile Objects. 403-422 2007 conf/ssd/2007 SSTD http://dx.doi.org/10.1007/978-3-540-73540-3_23 db/conf/ssd/sstd2007.html#LuHJX07