@article{turing1936a,
  annote = {Turing's famous demonstration of the formal limits on computation
	based on a proof that the {\em halting problem} is undecidable.},
  author = {Turing, Alan M.},
  interhash = {8ac1f5e961ff74849ab6f0c7348b9c9c},
  intrahash = {b51d7b5c67fb98e0117bc176ee5fd5cf},
  journal = {Proceedings of the London Mathematical Society},
  number = 42,
  pages = {230--265},
  title = {On Computable Numbers, with an Application to the {E}ntscheidungsproblem},
  url = {http://www.cs.helsinki.fi/u/gionis/cc05/OnComputableNumbers.pdf},
  volume = 2,
  year = 1936
}

@unpublished{Kahrs0X,
  author = {Kahrs, Stefan},
  interhash = {1b4787071a9247f5fe3c9327bd830468},
  intrahash = {e3ece6dc0b68b67ea6515ccd39d74ad3},
  title = {The Primitive Recursive Functions are Recursively Enumerable},
  url = {http://www.cs.kent.ac.uk/people/staff/smk/primrec.pdf},
  year = {200X}
}

@misc{klccne1952im,
  author = {Kleene, S.},
  interhash = {655ce304256a2845a50b6bbd1c2b14c4},
  intrahash = {e0272f0e1ae7d70858fb881d7ef83ab2},
  publisher = {Van Nostrand, New York},
  title = {{Introduction to Metamathematics}},
  year = 1952
}