Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819
Osawa, Kiyoteru (July 1959), "Spectral Classification of 533 B8-A2 Stars and the Mean Absolute Magnitude of a0 V Stars", Astrophysical Journal, 130: 159, Bibcode:1959ApJ...130..159O, doi:10.1086/146706
Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819
Osawa, Kiyoteru (July 1959), "Spectral Classification of 533 B8-A2 Stars and the Mean Absolute Magnitude of a0 V Stars", Astrophysical Journal, 130: 159, Bibcode:1959ApJ...130..159O, doi:10.1086/146706