Negueruela, I.; González-Fernández, C.; Dorda, R.; Marco, A.; Clark, J. S. The population of M-type supergiants in the starburst cluster Stephenson 2. Eas Publications Series. 2013, 60: 279. Bibcode:2013EAS....60..279N. arXiv:1303.1837. doi:10.1051/eas/1360032.
Fok, Thomas K. T; Nakashima, Jun-ichi; Yung, Bosco H. K; Hsia, Chih-Hao; Deguchi, Shuji. Maser Observations of Westerlund 1 and Comprehensive Considerations on Maser Properties of Red Supergiants Associated with Massive Clusters. The Astrophysical Journal. 2012, 760 (1): 65. Bibcode:2012ApJ...760...65F. arXiv:1209.6427. doi:10.1088/0004-637X/760/1/65.
Davies, B.; Figer, D. F.; Kudritzki, R. P.; MacKenty, J.; Najarro, F.; Herrero, A. A Massive Cluster of Red Supergiants at the Base of the Scutum‐Crux Arm. The Astrophysical Journal. 2007, 671 (1): 781–801. Bibcode:2007ApJ...671..781D. arXiv:0708.0821. doi:10.1086/522224.
Negueruela, I.; González-Fernández, C.; Dorda, R.; Marco, A.; Clark, J. S. The population of M-type supergiants in the starburst cluster Stephenson 2. Eas Publications Series. 2013, 60: 279. Bibcode:2013EAS....60..279N. arXiv:1303.1837. doi:10.1051/eas/1360032.
Fok, Thomas K. T; Nakashima, Jun-ichi; Yung, Bosco H. K; Hsia, Chih-Hao; Deguchi, Shuji. Maser Observations of Westerlund 1 and Comprehensive Considerations on Maser Properties of Red Supergiants Associated with Massive Clusters. The Astrophysical Journal. 2012, 760 (1): 65. Bibcode:2012ApJ...760...65F. arXiv:1209.6427. doi:10.1088/0004-637X/760/1/65.
Davies, B.; Figer, D. F.; Kudritzki, R. P.; MacKenty, J.; Najarro, F.; Herrero, A. A Massive Cluster of Red Supergiants at the Base of the Scutum‐Crux Arm. The Astrophysical Journal. 2007, 671 (1): 781–801. Bibcode:2007ApJ...671..781D. arXiv:0708.0821. doi:10.1086/522224.
Negueruela, I.; González-Fernández, C.; Dorda, R.; Marco, A.; Clark, J. S. The population of M-type supergiants in the starburst cluster Stephenson 2. Eas Publications Series. 2013, 60: 279. Bibcode:2013EAS....60..279N. arXiv:1303.1837. doi:10.1051/eas/1360032.
Cutri, R. M.; Skrutskie, M. F.; Van Dyk, S.; Beichman, C. A.; Carpenter, J. M.; Chester, T.; Cambresy, L.; Evans, T.; Fowler, J.; Gizis, J.; Howard, E.; Huchra, J.; Jarrett, T.; Kopan, E. L.; Kirkpatrick, J. D.; Light, R. M.; Marsh, K. A.; McCallon, H.; Schneider, S.; Stiening, R.; Sykes, M.; Weinberg, M.; Wheaton, W. A.; Wheelock, S.; Zacarias, N. VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003). VizieR On-line Data Catalog: II/246. Originally Published in: 2003yCat.2246....0C. 2003, 2246: 0. Bibcode:2003yCat.2246....0C.
Fok, Thomas K. T; Nakashima, Jun-ichi; Yung, Bosco H. K; Hsia, Chih-Hao; Deguchi, Shuji. Maser Observations of Westerlund 1 and Comprehensive Considerations on Maser Properties of Red Supergiants Associated with Massive Clusters. The Astrophysical Journal. 2012, 760 (1): 65. Bibcode:2012ApJ...760...65F. arXiv:1209.6427. doi:10.1088/0004-637X/760/1/65.
Davies, B.; Figer, D. F.; Kudritzki, R. P.; MacKenty, J.; Najarro, F.; Herrero, A. A Massive Cluster of Red Supergiants at the Base of the Scutum‐Crux Arm. The Astrophysical Journal. 2007, 671 (1): 781–801. Bibcode:2007ApJ...671..781D. arXiv:0708.0821. doi:10.1086/522224.