@Misc{HeinzMoses07,
  author =	 {Heinz, C. and Moses, B.},
  title =	 {The Listings Package},
  howpublished = {available on CTAN},
  year =	 2007
}


@Book{Newton1687,
  author =	 {Newton, I.},
  title = 	 {Philosophi\ae{} Naturalis Principia Mathematica},
  publisher = 	 {Royal Society of London for Improving Natural Knowledge},
  year = 	 1687}

@Article{Wittgenstein1921,
  author = 	 {Wittgenstein, L.},
  title = 	 {{L}ogisch-{P}hilosophische {A}bhandlung},
  journal = 	 {{A}nnalen der {N}aturphilosophie},
  year = 	 1921
}

@Book{Wittgenstein1981,
  author =	 {Wittgenstein, L. and C. K. Ogden (translator)},
  title = 	 {Tractatus Logico-Philosophicus},
  publisher = 	 {Routledge \& Kegan Paul},
  year = 	 1981}

