Tham khảo NGC_663

  1. ↑ O'Meara, S. J. (2002). The Caldwell objects, Deep-sky companions. Cambridge University Press. tr. 50–51. ISBN 978-0-521-82796-6.
  2. ↑ Pigulski, A.; Kopacki, G.; Kolaczkowski, Z. (2001). “The young open cluster NGC 663 and its Be stars”. Astronomy & Astrophysics. 376 (1): 144–153. Bibcode:2001A&A...376..144P. doi:10.1051/0004-6361:20010974.
  3. ↑ Marco, A.; Negueruela, I.; Motch, C. (2007). “Blue Stragglers, Be Stars and X-ray Binaries in Open Clusters”. ASP Conference Series. 361: 388. Bibcode:2007ASPC..361..388M.
  4. ↑ Phelps, Randy L.; Janes, Kenneth A. (1993). “Young open clusters as probes of the star-formation process. 2: Mass and luminosity functions of young open clusters”. Astronomical Journal. 106 (5): 1870–1884. Bibcode:1993AJ....106.1870P. doi:10.1086/116772.
  5. ↑ Negueruela, I.; González-Fernández, C.; Marco, A.; Clark, J. S. (2011). “A massive association around the obscured open cluster RSGC3”. Astronomy & Astrophysics. 528: A59. arXiv:1102.0028. Bibcode:2011A&A...528A..59N. doi:10.1051/0004-6361/201016102.
  6. ↑ Humphreys, R. M. (1978). “Studies of luminous stars in nearby galaxies. I. Supergiants and O stars in the Milky Way”. Astrophysical Journal Supplement Series. 38: 309–350. Bibcode:1978ApJS...38..309H. doi:10.1086/190559.