@misc{MannSchmidtSchauss2006,
  author    = {Matthias Mann and Manfred Schmidt-Schau{\"s}},
  title     = {How to prove similarity a precongruence in non-deterministic call-by-need lambda calculi},
  institution = {Informatik},
  series    = {Technical report Frank / Johann-Wolfgang-Goethe-Universit{\"a}t, Fachbereich Informatik und Mathematik, Institut f{\"u}r Informatik},
  number    = {22},
  year      = {2006}
}