Dopita, Michael A.; Sutherland, Ralph S. (2003). Astrophysics of the diffuse universe. Astronomy and astrophysics library. Springer. p. 128. ISBN 3-540-43362-7. 3-540-43362-7
Garstang, R. H. (May 1993). "Gaunt and his Factor". Bulletin of the American Astronomical Society. 25: 934. Bibcode:1993AAS...182.8104G. /wiki/Bibcode_(identifier)
Chandrasekhar, Subrahmanyan (1958). An introduction to the study of stellar structure. Astrophysical monographs. Courier Dover Publications. p. 262. ISBN 0-486-60413-6. {{cite book}}: ISBN / Date incompatibility (help) 0-486-60413-6