Baihua Zheng Jianliang Xu Wang-Chien Lee Dik Lun Lee Energy-Conserving Air Indexes for Nearest Neighbor Search. 48-66 http://dx.doi.org/10.1007/978-3-540-24741-8_5 2004 conf/edbt/2004 EDBT db/conf/edbt/edbt2004.html#ZhengXLL04