@inproceedings{SIGIR-2009-Baeza-YatesMH,
	author        = "Ricardo A. Baeza-Yates and Vanessa Murdock and Claudia Hauff",
	booktitle     = "{Proceedings of the 32nd International ACM SIGIR Conference on Research and Development in Information Retrieval}",
	doi           = "10.1145/1571941.1571971",
	isbn          = "978-1-60558-483-6",
	pages         = "163--170",
	publisher     = "{ACM}",
	title         = "{Efficiency trade-offs in two-tier web search systems}",
	year          = 2009,
}