Abt, H. A.; Levy, S. G. (1985). "Improved study of metallic-line binaries". The Astrophysical Journal Supplement Series. 59: 229. Bibcode:1985ApJS...59..229A. doi:10.1086/191070.
"The Colour of Stars". Australia Telescope, Outreach and Education. Commonwealth Scientific and Industrial Research Organisation. December 21, 2004. Archived from the original on 2013-12-03. Retrieved 2012-01-16.
Abt, H. A.; Levy, S. G. (1985). "Improved study of metallic-line binaries". The Astrophysical Journal Supplement Series. 59: 229. Bibcode:1985ApJS...59..229A. doi:10.1086/191070.
"The Colour of Stars". Australia Telescope, Outreach and Education. Commonwealth Scientific and Industrial Research Organisation. December 21, 2004. Archived from the original on 2013-12-03. Retrieved 2012-01-16.