@conference {liu2009clustering,
	title = {Clustering queries for better document ranking},
	booktitle = {Proceedings of the 18th ACM conference on Information and knowledge management},
	year = {2009},
	pages = {1569{\textendash}1572},
	publisher = {ACM},
	organization = {ACM},
	author = {Liu, Yi and Zhang, Liangjie and Song, Ruihua and Jian-Yun Nie and Wen, Ji-Rong}
}
