@article{Martin&Gibbons2001:Semantics,
  title = "On the Semantics of Nested Datatypes",
  author = "Clare Martin and Jeremy Gibbons",
  year = "2001",
  journal = "Information Processing Letters",
  month = "dec",
  number = "5",
  pages = "233--238",
  url = "http://www.cs.ox.ac.uk/people/jeremy.gibbons/publications/semantics.ps.gz",
  volume = "80",
}