@article{BelagaMignotte1999,
  author    = {{Edward Belaga and Maurice Mignotte}},
  title     = {{Embedding the $3x+1$ Conjecture in a $3x+d$ Context}},
  journal   = {{Experimental Math.}},
  year      = {{1999}},
  volume    = {{7}},
  pages     = {{145--151}},
  note      = {{MR 200d:11034}},
}