@article{Domenici2009,
  author    = {{Diego Domenici}},
  title     = {{A few observations on the Collatz problem}},
  journal   = {{Inter. J. Appl. Math. Stat.}},
  year      = {{2009}},
  volume    = {{14}},
  pages     = {{97--107}},
  note      = {{MR 2524878}},
}