Chi Tian Taro Tezuka Satoshi Oyama Keishi Tajima Katsumi Tanaka Web Search Improvement Based on Proximity and Density of Miltiple Keywords. 133 2006 conf/icde/2006w ICDE Workshops http://doi.ieeecomputersociety.org/10.1109/ICDEW.2006.164 db/conf/icde/icdew2006.html#TianTOTT06