Goldsbury, Ryan; et al. (2010), "The ACS Survey of Galactic Globular Clusters. X. New Determinations of Centers for 65 Clusters", The Astronomical Journal, 140 (6): 1830–1837, Bibcode:2010AJ....140.1830G, doi:10.1088/0004-6256/140/6/1830Parameter |month= yang tidak diketahui akan diabaikan (bantuan)
Sollima, A.; et al. (2008), "The correlation between blue straggler and binary fractions in the core of Galactic globular clusters", Astronomy and Astrophysics, 481 (3): 701–704, Bibcode:2008A&A...481..701S, doi:10.1051/0004-6361:20079082Parameter |month= yang tidak diketahui akan diabaikan (bantuan)
harvard.edu
adsabs.harvard.edu
Shapley, Harlow; Sawyer, Helen B. (1927), "A Classification of Globular Clusters", Harvard College Observatory Bulletin (849): 11–14, Bibcode:1927BHarO.849...11S.Parameter |month= yang tidak diketahui akan diabaikan (bantuan)
Goldsbury, Ryan; et al. (2010), "The ACS Survey of Galactic Globular Clusters. X. New Determinations of Centers for 65 Clusters", The Astronomical Journal, 140 (6): 1830–1837, Bibcode:2010AJ....140.1830G, doi:10.1088/0004-6256/140/6/1830Parameter |month= yang tidak diketahui akan diabaikan (bantuan)
Sollima, A.; et al. (2008), "The correlation between blue straggler and binary fractions in the core of Galactic globular clusters", Astronomy and Astrophysics, 481 (3): 701–704, Bibcode:2008A&A...481..701S, doi:10.1051/0004-6361:20079082Parameter |month= yang tidak diketahui akan diabaikan (bantuan)
Kaluzny, J.; et al. (2010), "The Cluster AgeS Experiment (CASE). Variable Stars in the Globular Cluster M55", Acta Astronomica, 60 (3): 245–260, Bibcode:2010AcA....60..245KParameter |month= yang tidak diketahui akan diabaikan (bantuan)
u-strasbg.fr
simbad.u-strasbg.fr
"NGC 6809", SIMBAD Astronomical Database, diakses tanggal 2006-11-16
