@article{WangYu2008,
  author    = {{Wang, Xing-yuan and Yu, Xue-jing}},
  title     = {{Dynamics of the generalized $3x+1$ function determined by its fractal images}},
  journal   = {{Progress Natural Science (English Edition)}},
  year      = {{2008}},
  volume    = {{18}},
  pages     = {{217--223}},
  note      = {{MR 2009i:37020}},
}