@misc{SchmidtSchaussSabelHarwath2009,
  author    = {Manfred Schmidt-Schauß and David Sabel and Frederik Harwath},
  title     = {Contextual equivalence in lambda-calculi extended with letrec and with a parametric polymorphic type system},
  booktitle = {Technical report Frank / Johann-Wolfgang-Goethe-Universit{\"a}t, Fachbereich Informatik und Mathematik, Institut f{\"u}r Informatik ; 36},
  url       = {http://www.ki.informatik.uni-frankfurt.de/papers/frank/poly-type-IB36.pdf},
  institution = {Informatik},
  series    = {Technical report Frank / Johann-Wolfgang-Goethe-Universit{\"a}t, Fachbereich Informatik und Mathematik, Institut f{\"u}r Informatik},
  number    = {36},
  type      = {workingpaper},
  pages     = {1 -- 26},
  year        = {2009},
}