@article{ButtsworthMatthews1990,
  author    = {{Robert N. Buttsworth and Keith R. Matthews}},
  title     = {{On some Markov matrices arising from the generalized Collatz mapping}},
  journal   = {{Acta Arithmetica}},
  year      = {{1990}},
  volume    = {{55}},
  pages     = {{43--57}},
  note      = {{MR 92a:11016}},
}