Learning to rank with ties.

@inproceedings{zhou-2008-learning, author = {Ke Zhou and Gui-Rong Xue and Hongyuan Zha and Yong Yu}, editor = {Sung-Hyon Myaeng and Douglas W. Oard and Fabrizio Sebastiani and Tat-Seng Chua and Mun-Kew Leong}, title = {{Learning to rank with ties}}, booktitle = {{Proceedings of the 31st Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, SIGIR 2008, Singapore, July 20-24, 2008}}, pages = {275--282}, publisher = {ACM}, year = {2008}, url = {https://doi.org/10.1145/1390334.1390382}, doi = {https://doi.org/10.1145/1390334.1390382} }