@article{neubig16cl,
    title = {Optimization for Statistical Machine Translation: A Survey},
    author = {Graham Neubig and Taro Watanabe},
    journal = {Computational Linguistics},
    month = {March},
    volume = {42},
    number = {1},
    pages = {1----54},
    url = {http://www.phontron.com/paper/neubig16cl.pdf},
    year = {2016}
}