Adams, Walter S.; et al. (1935), "The Spectroscopic Absolute Magnitudes and Parallaxes of 4179 Stars", Astrophysical Journal, 81: 187, Bibcode:1935ApJ....81..187A, doi:10.1086/143628.
Adams, Walter S.; et al. (1935), "The Spectroscopic Absolute Magnitudes and Parallaxes of 4179 Stars", Astrophysical Journal, 81: 187, Bibcode:1935ApJ....81..187A, doi:10.1086/143628.