@inproceedings{aregularizedcompetitionmodelforquestion,
  title = {A Regularized Competition Model for Question Difficulty Estimation in Community Question Answering Services},
  author = {Quan Wang and Jing Liu and Bin Wang and Li Guo},
  year = {2014},
  booktitle = {EMNLP 2014 10},
  url = {https://aclanthology.org/D14-1118},
}