@article{einstein1905tragheit,
  title = {Ist die Trägheit eines Körpers von seinem Energieinhalt abhängig?},
  author = {Einstein, Albert},
  journal = {Annalen der Physik},
  volume = {323},
  number = {13},
  pages = {639-641},
  year = {1905},
}

@article{tolkamp10cows,
  title = {Are cows more likely to lie down the longer they stand?},
  author = {Tolkamp, Bert J. and Haskell, Marie J. and Langford, Fritha M. and Roberts, David J. and Morgan, Colin A.},
  journal = {Applied Animal Behaviour Science},
  volume = {124},
  number = {1-2},
  pages = {1-10},
  year = {2010},
  publisher = {Elsevier},
}
