Negueruela, I.; Marco, A.; González-Fernández, C.; Jiménez-Esteban, F.; Clark, J. S.; Garcia, M.; Solano, E. Red supergiants around the obscured open cluster Stephenson 2. Astronomy & Astrophysics. 2012, 547: A15. Bibcode:2012A&A...547A..15N. arXiv:1208.3282. doi:10.1051/0004-6361/201219540.
Negueruela, I.; Marco, A.; González-Fernández, C.; Jiménez-Esteban, F.; Clark, J. S.; Garcia, M.; Solano, E. Red supergiants around the obscured open cluster Stephenson 2. Astronomy & Astrophysics. 2012, 547: A15. Bibcode:2012A&A...547A..15N. arXiv:1208.3282. doi:10.1051/0004-6361/201219540.
Negueruela, I.; Marco, A.; González-Fernández, C.; Jiménez-Esteban, F.; Clark, J. S.; Garcia, M.; Solano, E. Red supergiants around the obscured open cluster Stephenson 2. Astronomy & Astrophysics. 2012, 547: A15. Bibcode:2012A&A...547A..15N. arXiv:1208.3282. doi:10.1051/0004-6361/201219540.