Johnson, H. L.; Morgan, W. W. (1953). "Fundamental stellar photometry for standards of spectral type on the Revised System of the Yerkes Spectral Atlas". The Astrophysical Journal. 117: 313. Bibcode:1953ApJ...117..313J. doi:10.1086/145697.
Garrison, R. F.; Gray, R. O. (1994). "The Late B-Type Stars: Refined MK Classification, Confrontation with Stromgren Photometry, and the Effects of Rotation". The Astronomical Journal. 107: 1556. Bibcode:1994AJ....107.1556G. doi:10.1086/116967.
Lesh, Janet Rountree (1968). "The Kinematics of the Gould Belt: An Expanding Group?". The Astrophysical Journal Supplement Series. 17: 371. Bibcode:1968ApJS...17..371L. doi:10.1086/190179.
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Pickering, Edward Charles (1908). "Revised Harvard photometry : a catalogue of the positions, photometric magnitudes and spectra of 9110 stars, mainly of the magnitude 6.50, and brighter observed with the 2 and 4 inch meridian photometers". Annals of the Astronomical Observatory of Harvard College. 50: 1. Bibcode:1908AnHar..50....1P.
Morgan, William Wilson; Keenan, Philip Childs; Kellman, Edith (1943). An atlas of stellar spectra, with an outline of spectral classification. Chicago, Ill: The University of Chicago press. Bibcode:1943assw.book.....M.
Johnson, H. L.; Morgan, W. W. (1953). "Fundamental stellar photometry for standards of spectral type on the Revised System of the Yerkes Spectral Atlas". The Astrophysical Journal. 117: 313. Bibcode:1953ApJ...117..313J. doi:10.1086/145697.
Morgan, W. W.; Abt, Helmut A.; Tapscott, J. W. (1978). Revised MK Spectral Atlas for stars earlier than the sun. Bibcode:1978rmsa.book.....M.
Garrison, R. F.; Gray, R. O. (1994). "The Late B-Type Stars: Refined MK Classification, Confrontation with Stromgren Photometry, and the Effects of Rotation". The Astronomical Journal. 107: 1556. Bibcode:1994AJ....107.1556G. doi:10.1086/116967.
Lesh, Janet Rountree (1968). "The Kinematics of the Gould Belt: An Expanding Group?". The Astrophysical Journal Supplement Series. 17: 371. Bibcode:1968ApJS...17..371L. doi:10.1086/190179.