@article{Hin05Chu,
  title = "{Theoretical Pearl:} {C}hurch numerals, twice!",
  author = "Hinze, Ralf",
  year = "2005",
  journal = "JFP",
  month = "jan",
  number = "1",
  pages = "1-13",
  volume = "15",
  doi = "10.1017/S0956796804005313",
}