@article{AndreiKudlekNiculescu2000,
  author    = {{Stefan Andrei and Manfred Kudlek and Radu Stefan Niculescu}},
  title     = {{Some results on the Collatz problem}},
  journal   = {{Acta Informatica}},
  year      = {{2000}},
  volume    = {{37}},
  pages     = {{145--160}},
  note      = {{MR 2002c:11022}},
}