@misc{wikipedia:Twelvefold-Way,
   author = "Wikipedia",
   title = "Twelvefold way --- Wikipedia{,} The Free Encyclopedia",
   year = "2016",
   url = "https://en.wikipedia.org/w/index.php?title=Twelvefold_way&oldid=742521341",
   note = "[Online; accessed 4-October-2016]"
}

@book{stanley-2012,
   title = "Enumerative Combinatorics. Volume 1",
   author = "Stanley, Richard P.",
   series = "Cambridge studies in advanced mathematics",
   publisher = "Cambridge University Press",
   address = "Cambridge, New York",
   edition = "Second",
   year = "2012"
}

@book{bogart-2004,
   title = "Combinatorics Through Guided Discovery",
   author = "Bogart, Kenneth P.",
   url = "https://math.dartmouth.edu/news-resources/electronic/kpbogart/ComboNoteswHints11-06-04.pdf",
   year = "2004"
}

@article{Card_Partitions-AFP,
  author  = {Lukas Bulwahn},
  title   = {Cardinality of Set Partitions},
  journal = {Archive of Formal Proofs},
  month   = dec,
  year    = 2015,
  note    = {\url{http://isa-afp.org/entries/Card_Partitions.shtml},
            Formal proof development},
  ISSN    = {2150-914x},
}

@article{Card_Number_Partitions-AFP,
  author  = {Lukas Bulwahn},
  title   = {Cardinality of Number Partitions},
  journal = {Archive of Formal Proofs},
  month   = jan,
  year    = 2016,
  note    = {\url{http://isa-afp.org/entries/Card_Number_Partitions.shtml},
            Formal proof development},
  ISSN    = {2150-914x},
}

@article{Card_Multisets-AFP,
  author  = {Lukas Bulwahn},
  title   = {Cardinality of Multisets},
  journal = {Archive of Formal Proofs},
  month   = jun,
  year    = 2016,
  note    = {\url{http://isa-afp.org/entries/Card_Multisets.shtml},
            Formal proof development},
  ISSN    = {2150-914x},
}