@article{KraussN-AFP,
  author  = {Alexander Krauss and Tobias Nipkow},
  title   = {Regular Sets and Expressions},
  journal = {Archive of Formal Proofs},
  year    = 2010,
  note    = {\url{http://isa-afp.org/entries/Regular-Sets.shtml},
            Formal proof development},
  ISSN    = {2150-914x}
}

@inproceedings{TraytelN-ICFP13,
  author =       {Dmitriy Traytel and Tobias Nipkow},
  title =        {Verified Decision Procedures for {MSO} on Words Based on
                  Derivatives of Regular Expressions},
  booktitle =    {{P}roc.\ {I}nt.\ {C}onf.\ {F}unctional {P}rogramming, {ICFP} 2013},
  editor =       {G. Morrisett and T. Uustalu},
  pages =        {3--12},
  year =         2013,
  publisher =    {ACM}
}