@techreport{Hin98Pol,
  title = "Polytypic Functions Over Nested Datatypes",
  author = "Hinze, Ralf",
  year = "1998",
  institution = "Institut f{\"u}r Informatik III, Universit{\"a}t Bonn",
  month = "oct",
  number = "IAI-TR-98-10",
}