@article{BergMeinardus1995,
  author    = {{Lothar Berg and Günter Meinardus}},
  title     = {{The 3n+1 Collatz Problem and Functional Equations}},
  journal   = {{Rostock Math. Kolloq.}},
  year      = {{1995}},
  volume    = {{48}},
  pages     = {{11--18}},
  note      = {{MR 97e:11034}},
}