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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 Journal117: 313.Bibcode:1953ApJ...117..313J.doi:10.1086/145697.ISSN0004-637X.
Morgan,W. W;Abt,Helmut A;Tapscott,J. W(1978).“Revised MK Spectral Atlas for stars earlier than the sun”.Williams Bay: Yerkes Observatory.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 Journal107: 1556.Bibcode:1994AJ....107.1556G.doi:10.1086/116967.ISSN0004-6256.
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 Journal117: 313.Bibcode:1953ApJ...117..313J.doi:10.1086/145697.ISSN0004-637X.
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 Journal107: 1556.Bibcode:1994AJ....107.1556G.doi:10.1086/116967.ISSN0004-6256.
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 Journal117: 313.Bibcode:1953ApJ...117..313J.doi:10.1086/145697.ISSN0004-637X.
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 Journal107: 1556.Bibcode:1994AJ....107.1556G.doi:10.1086/116967.ISSN0004-6256.