Levesque, E. M.; Massey, P.; Olsen, K. A. G.; Plez, B.; Josselin, E.; Maeder, A.; Meynet, G. The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not as Cool as We Thought. The Astrophysical Journal. 2005, 628 (2): 973. Bibcode:2005ApJ...628..973L. arXiv:astro-ph/0504337. doi:10.1086/430901.
Levesque, E. M.; Massey, P.; Olsen, K. A. G.; Plez, B.; Josselin, E.; Maeder, A.; Meynet, G. The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not as Cool as We Thought. The Astrophysical Journal. 2005, 628 (2): 973. Bibcode:2005ApJ...628..973L. arXiv:astro-ph/0504337. doi:10.1086/430901.
Dyck, H. M.; Benson, J. A.; Van Belle, G. T.; Ridgway, S. T. Radii and Effective Temperatures for K and M Giants and Supergiants. The Astronomical Journal. 1996, 111: 1705. Bibcode:1996AJ....111.1705D. doi:10.1086/117910.
Stephenson, C. B. A Possible New Galactic Cluster Involving δ Lyrae. Publications of the Astronomical Society of the Pacific. 1959, 71: 145. Bibcode:1959PASP...71..145S. doi:10.1086/127349.
Levesque, E. M.; Massey, P.; Olsen, K. A. G.; Plez, B.; Josselin, E.; Maeder, A.; Meynet, G. The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not as Cool as We Thought. The Astrophysical Journal. 2005, 628 (2): 973. Bibcode:2005ApJ...628..973L. arXiv:astro-ph/0504337. doi:10.1086/430901.
Dyck, H. M.; Benson, J. A.; Van Belle, G. T.; Ridgway, S. T. Radii and Effective Temperatures for K and M Giants and Supergiants. The Astronomical Journal. 1996, 111: 1705. Bibcode:1996AJ....111.1705D. doi:10.1086/117910.
Stephenson, C. B. A Possible New Galactic Cluster Involving δ Lyrae. Publications of the Astronomical Society of the Pacific. 1959, 71: 145. Bibcode:1959PASP...71..145S. doi:10.1086/127349.