[1] AN ATLAS OF STELLAR SPECTRA
WITH AN OUTLINE OF SPECTRAL CLASSIFICATION, W.W. Morgan, P.C. Keenan & E. Kellman, 1943, Chicago, Ill., The University of Chicago press
Tabela 5, William D. Vacca; Catharine D. Garmany & J. Michael Shull (abril de 1996). «The Lyman-Continuum Fluxes and Stellar Parameters of O and Early B-Type Stars». Astrophysical Journal. 460: 914–931. Bibcode:1996ApJ...460..914V. doi:10.1086/177020
Tabela 5, William D. Vacca; Catharine D. Garmany & J. Michael Shull (abril de 1996). «The Lyman-Continuum Fluxes and Stellar Parameters of O and Early B-Type Stars». Astrophysical Journal. 460: 914–931. Bibcode:1996ApJ...460..914V. doi:10.1086/177020