@inproceedings{CIKM-2012-LiuLCBZ,
	author        = "Jingjing Liu and Chang Liu and Michael J. Cole and Nicholas J. Belkin and Xiangmin Zhang",
	booktitle     = "{Proceedings of the 21st ACM International Conference on Information and Knowledge Management}",
	doi           = "10.1145/2396761.2398434",
	isbn          = "978-1-4503-1156-4",
	pages         = "1313--1322",
	publisher     = "{ACM}",
	title         = "{Exploring and predicting search task difficulty}",
	year          = 2012,
}