Crawford, D. L.; Barnes, J. V.; Golson, J. C. (1971). "Four-color, Hbeta, and UBV photometry for bright B-type stars in the northern hemisphere". The Astronomical Journal. 76: 1058. Bibcode:1971AJ.....76.1058C. doi:10.1086/111220.
Crawford, D. L.; Barnes, J. V.; Golson, J. C. (1971). "Four-color, Hbeta, and UBV photometry for bright B-type stars in the northern hemisphere". The Astronomical Journal. 76: 1058. Bibcode:1971AJ.....76.1058C. doi:10.1086/111220.