@book{ BB08055481,
  author    = "Tetens, Holm",
  title     = "Wittgensteins "Tractatus" : ein Kommentar",
  publisher = "Philipp Reclam",
  year      = "2009",
  series    = "Universal-Bibliothek",
  number    = "Nr. 18624",
  URL       = "http://ci.nii.ac.jp/ncid/BB08055481"
}