«Rotation of the Andromeda Nebula from a Spectroscopic Survey of Emission Regions». Astrophysical Journal, 159, 1970, pàg. 379. Bibcode: 1970ApJ...159..379R. DOI: 10.1086/150317.
Zwicky, F. «Die Rotverschiebung von extragalaktischen Nebeln». Helvetica Physica Acta, 6, 1933, p. 110–127. See also Zwicky, F. «On the Masses of Nebulae and of Clusters of Nebulae». Astrophysical Journal, 86, 1937, p. 217. DOI: 10.1086/143864.
«Rotational Properties of 21 Sc Galaxies with a Large Range of Luminosities and Radii from NGC 4605 (R=4kpc) to UGC 2885 (R=122kpc)». Astrophysical Journal, 238, 1980, pàg. 471. Bibcode: 1980ApJ...238..471R. DOI: 10.1086/158003.
«Rotation of the Andromeda Nebula from a Spectroscopic Survey of Emission Regions». Astrophysical Journal, 159, 1970, pàg. 379. Bibcode: 1970ApJ...159..379R. DOI: 10.1086/150317.
«Rotational Properties of 21 Sc Galaxies with a Large Range of Luminosities and Radii from NGC 4605 (R=4kpc) to UGC 2885 (R=122kpc)». Astrophysical Journal, 238, 1980, pàg. 471. Bibcode: 1980ApJ...238..471R. DOI: 10.1086/158003.