Morgan, W. W.; Abt, H. A. (February 1972), "The spectral classification of the F stars of intermediate luminosity", Astronomical Journal, 77: 35–37, Bibcode:1972AJ.....77...35M, doi:10.1086/111242
Appenzeller, Immo (April 1967), "MK Spectral Types for 185 Bright Stars", Publications of the Astronomical Society of the Pacific, 79 (467): 102, Bibcode:1967PASP...79..102A, doi:10.1086/128449.
Morgan, W. W.; Abt, H. A. (February 1972), "The spectral classification of the F stars of intermediate luminosity", Astronomical Journal, 77: 35–37, Bibcode:1972AJ.....77...35M, doi:10.1086/111242
Appenzeller, Immo (April 1967), "MK Spectral Types for 185 Bright Stars", Publications of the Astronomical Society of the Pacific, 79 (467): 102, Bibcode:1967PASP...79..102A, doi:10.1086/128449.