Hogg, A. R. (1958), "Photometric observations of 244 bright stars", Mount Stromlo Observatory Mimeogram, 2: 1, Bibcode:1958MtSOM...2....1H.
Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.