@article{Gibbons*2006:Enumerating,
  title = "Enumerating the Rationals",
  author = "Jeremy Gibbons and David Lester and Richard Bird",
  year = "2006",
  journal = "Journal of Functional Programming",
  number = "4",
  url = "http://www.comlab.ox.ac.uk/oucl/work/jeremy.gibbons/publications/rationals.pdf",
  volume = "16",
  doi = "10.1017/S0956796806005880",
}