@article{LagariasSoundararajan2006,
  author    = {{Jeffrey C. Lagarias and K. Soundararajan}},
  title     = {{Benford's Law for the $3x+1$ Function}},
  journal   = {{J. London Math. Soc.}},
  year      = {{2006}},
  volume    = {{74}},
  pages     = {{289--303}},
  note      = {{MR 2007h:37007}},
}