@article{DolanGilmanManickam1987,
  author    = {{James M. Dolan, Albert  F. Gilman and Shan Manickam}},
  title     = {{A generalization of Everett's result on the Collatz $3x  +  1$ problem}},
  journal   = {{Adv. Appl. Math.}},
  year      = {{1987}},
  volume    = {{8}},
  pages     = {{405--409}},
  note      = {{MR 89a:11018}},
}