@misc{Friis_F._R._Tychonis_1867,
 author={Friis, F. R.},
 address={Havniae},
 howpublished={online},
 year={1867},
 publisher={Prostat Lipsiae Apud Guil. Engelmann},
 language={lat},
 title={Tychonis Brahe Dani Observationes Septem Cometarium},
 keywords={Tycho Brahe, ephemeris of comets},
}