report{Schmidhuber:03gm1,
author ={J. Schmidhuber},
title ={G\"{o}del machines: self-referential universal problem
solvers making provably optimal self-improvements},
number ={IDSIA-19-03,  arXiv:cs.LO/0309048 v1},
institution ={IDSIA},
address={Manno-Lugano, Switzerland},
month = {September},
year   = {2003}}