Eisenhauer, F.; Schdel, R.; Genzel, R.; Ott, T.; Tecza, M.; Abuter, R.; Eckart, A.; Alexander, T. (2003), «A Geometric Determination of the Distance to the Galactic Center», The Astrophysical Journal, 597 (2): L121, Bibcode:2003ApJ...597L.121E, arXiv:astro-ph/0306220, doi:10.1086/380188
Bessel, Friedrich (1839). «On the parallax of the star 61 Cygni». London and Edinburgh Philosophical Magazine and Journal of Science. 14: 68–72 Bessel's statement that light employs 10.3 years to traverse the distance.
Ule, Otto (1851). «Was wir in den Sternen lesen». Deutsches Museum: Zeitschrift für Literatur, Kunst und Öffentliches Leben. 1: 721–738
Eisenhauer, F.; Schdel, R.; Genzel, R.; Ott, T.; Tecza, M.; Abuter, R.; Eckart, A.; Alexander, T. (2003), «A Geometric Determination of the Distance to the Galactic Center», The Astrophysical Journal, 597 (2): L121, Bibcode:2003ApJ...597L.121E, arXiv:astro-ph/0306220, doi:10.1086/380188
Eisenhauer, F.; Schdel, R.; Genzel, R.; Ott, T.; Tecza, M.; Abuter, R.; Eckart, A.; Alexander, T. (2003), «A Geometric Determination of the Distance to the Galactic Center», The Astrophysical Journal, 597 (2): L121, Bibcode:2003ApJ...597L.121E, arXiv:astro-ph/0306220, doi:10.1086/380188
Junor, W.; Biretta, J. A. (1994), «The Inner Light-Month of the M87 Jet», in: Zensus, J. Anton; Kellermann; Kenneth I., Compact Extragalactic Radio Sources, Proceedings of the NRAO workshop held at Socorro, New Mexico, February 11–12, 1994, Green Bank, WV: National Radio Astronomy Observatory (NRAO), p. 97, Bibcode:1994cers.conf...97J