@article{UrataSuzukiKajita1997,
  author    = {{Toshio Urata and Katsufumi Suzuki and Hisao Kajita}},
  title     = {{Collatz Problem II}},
  journal   = {{Epsilon (The Bulletin of the Society of Mathematics Education of Aichi Univ. of Education) [Aichi Kyoiku Daigaku Sugaku Kyoiku Gakkai shi]}},
  year      = {{1997}},
  volume    = {{39}},
  pages     = {{121--129}},
}