@article{WuHuang2001,
  author    = {{Wu, Jia Bang and Huang, Guo Lin}},
  title     = {{On the traditional iteration and the elongate iteration of the $3N+1$ conjecture}},
  journal   = {{Journal of South-Central University for Nationalities. Natural Sciences Ed.}},
  year      = {{2001}},
  volume    = {{21}},
  number    = {{4}},
}