@article{Chamberland1996,
  author    = {{Marc Chamberland}},
  title     = {{A Continuous Extension of the $3x+1$ Problem to the Real Line}},
  journal   = {{Dynamics of Continuous, Discrete and Impulsive Dynamical Systems}},
  year      = {{1996}},
  volume    = {{2}},
  pages     = {{495--509}},
  note      = {{MR 97f:39031}},
}