@conference {gao2009smoothing,
	title = {Smoothing clickthrough data for web search ranking},
	booktitle = {Proceedings of the 32nd international ACM SIGIR conference on Research and development in information retrieval},
	year = {2009},
	pages = {355{\textendash}362},
	publisher = {ACM},
	organization = {ACM},
	author = {Gao, Jianfeng and Yuan, Wei and Li, Xiao and Deng, Kefeng and Jian-Yun Nie}
}
