@article{Barthwal_Norrish_14,
    author           = {Barthwal, Aditi and Norrish, Michael},
    doi              = {10.1016/j.jcss.2013.05.003},
    journal          = {Journal of Computer and System Sciences},
    keywords         = {context-free languages, language theory},
    month            = mar,
    number           = {2},
    pages            = {346--362},
    paperurl         = {https://trustworthy.systems/publications/nicta_full_text/7411.pdf},
    title            = {A mechanisation of some context-free language theory in {HOL4}},
    volume           = {80},
    year             = {2014}
  }