@article{Boyd1985,
  author    = {{David W. Boyd}},
  title     = {{Which rationals are ratios of Pisot sequences?}},
  journal   = {{Canad. Math. Bull.}},
  year      = {{1985}},
  volume    = {{28}},
  pages     = {{343--349}},
  note      = {{MR 86j:11078}},
}