@inproceedings{CIKM-2009-ZhuCWZWC,
	author        = "Zeyuan Allen Zhu and Weizhu Chen and Tao Wan and Chenguang Zhu and Gang Wang and Zheng Chen",
	booktitle     = "{Proceedings of the 18th ACM International Conference on Information and Knowledge Management}",
	doi           = "10.1145/1645953.1646255",
	isbn          = "978-1-60558-512-3",
	pages         = "1883--1886",
	publisher     = "{ACM}",
	title         = "{To divide and conquer search ranking by learning query difficulty}",
	year          = 2009,
}