@inproceedings{SIGIR-2007-XuL07a,
	author        = "Jingfang Xu and Xing Li",
	booktitle     = "{Proceedings of the 30th International ACM SIGIR Conference on Research and Development in Information Retrieval}",
	doi           = "10.1145/1277741.1277898",
	isbn          = "978-1-59593-597-7",
	pages         = "765--766",
	publisher     = "{ACM}",
	title         = "{Learning to rank collections}",
	year          = 2007,
}