@article{ApplegateLagarias1995a,
  author    = {{David Applegate and Jeffrey C. Lagarias}},
  title     = {{Density Bounds for the $3x+1$ Problem I. Tree-Search Method}},
  journal   = {{Math. Comp.}},
  year      = {{1995}},
  volume    = {{64}},
  pages     = {{411--426}},
  url       = {{https://www.researchgate.net/profile/Jeffrey-Lagarias/publication/266310495_Density_bounds_for_the_3x1_problem_I_Tree-search_method_II_Krasikov_inequalities/links/02e7e53b458dd279aa000000/Density-bounds-for-the-3x-1-problem-I-Tree-search-method-II-Krasikov-inequalities.pdf}},
  note      = {{MR 95c:11024}},
}