@article{Graf,
  author    = {Johannes Graf},
  title     = {Wilhelm Foerster, Vater der Zeitverteilung im Deutschen Kaiserreich},
  series = {PTB-Mitteilungen},
  volume    = {119.2009},
  number    = {3},
  issn      = {0030-834X},
  pages     = {209 -- 215},
  language  = {de}
}