@inproceedings{li-eisner-2009-first,
    title = "First- and Second-Order Expectation Semirings with Applications to Minimum-Risk Training on Translation Forests",
    author = "Li, Zhifei  and
      Eisner, Jason",
    editor = "Koehn, Philipp  and
      Mihalcea, Rada",
    booktitle = "Proceedings of the 2009 Conference on Empirical Methods in Natural Language Processing",
    month = aug,
    year = "2009",
    address = "Singapore",
    publisher = "Association for Computational Linguistics",
    url = "https://aclanthology.org/D09-1005/",
    pages = "40--51"
}