@article{Martin*2004:Disciplined,
  title = "Disciplined, efficient, generalised folds for nested datatypes",
  author = "Clare Martin and Jeremy Gibbons and Ian Bayley",
  year = "2004",
  journal = "Formal Aspects of Computing",
  number = "1",
  pages = "19-35",
  url = "http://www.comlab.ox.ac.uk/oucl/work/jeremy.gibbons/publications/efolds.pdf",
  volume = "16",
}