@inproceedings{merrill-etal-2020-formal,
    title = "A Formal Hierarchy of {RNN} Architectures",
    author = "Merrill, William  and
      Weiss, Gail  and
      Goldberg, Yoav  and
      Schwartz, Roy  and
      Smith, Noah A.  and
      Yahav, Eran",
    editor = "Jurafsky, Dan  and
      Chai, Joyce  and
      Schluter, Natalie  and
      Tetreault, Joel",
    booktitle = "Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics",
    month = jul,
    year = "2020",
    address = "Online",
    publisher = "Association for Computational Linguistics",
    url = "https://preview.aclanthology.org/fix-sig-urls/2020.acl-main.43/",
    doi = "10.18653/v1/2020.acl-main.43",
    pages = "443--459"
}