Yunjun Gao Gencai Chen Qing Li Baihua Zheng Chun Li Processing Mutual Nearest Neighbor Queries for Moving Object Trajectories. 116-123 2008 MDM http://doi.ieeecomputersociety.org/10.1109/MDM.2008.17 conf/mdm/2008 db/conf/mdm/mdm2008.html#GaoCLZL08