@article{Wu1992,
  author    = {{Wu, Jia Bang}},
  title     = {{A tendency of the proportion  of consecutive numbers of 
the same height in the Collatz problem}},
  journal   = {{J. Huazhong (Central China) Univ. Sci. Technol.  [Hua zhong gong xue yuan]}},
  year      = {{1992}},
  volume    = {{20}},
  pages     = {{171--174}},
  note      = {{MR 94b:11024, Zbl. 766.11013}},
}