Huanhuan Cao Daxin Jiang Jian Pei Qi He Zhen Liao Enhong Chen Hang Li Context-aware query suggestion by mining click-through and session data. 875-883 2008 KDD http://doi.acm.org/10.1145/1401890.1401995 conf/kdd/2008 db/conf/kdd/kdd2008.html#CaoJPHLCL08