@inproceedings {4116,
	title = {Improving Retrieval Accuracy by Weighting Document Types With Clickthrough Data},
	booktitle = {International Conference on Research and Development in Information Retrieval (SIGIR)},
	year = {2007},
	doi = {10.1145/1277741.1277895},
	author = {Peter C. K. Yeung and Charles Clarke and Stefan B{\"u}ttcher}
}
