ref.bib

@article{einstein,
  author =       "Albert Einstein",
  title =        "{Zur Elektrodynamik bewegter K{\"o}rper}. ({German})
                 [{On} the electrodynamics of moving bodies]",
  journal =      "Annalen der Physik",
  volume =       "322",
  number =       "10",
  pages =        "891--921",
  year =         "1905",
  DOI =          "http://dx.doi.org/10.1002/andp.19053221004",
  keywords =     "physics"
}

@book{dirac,
  title={The Principles of Quantum Mechanics},
  author={Paul Adrien Maurice Dirac},
  isbn={9780198520115},
  series={International series of monographs on physics},
  year={1981},
  publisher={Clarendon Press},
  keywords = {physics}
}