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Goldsbury, Ryan; Richer, Harvey B.; Anderson, Jay; Dotter, Aaron; Sarajedini, Ata; Woodley, Kristin (Aralık 2010), "The ACS Survey of Galactic Globular Clusters. X. New Determinations of Centers for 65 Clusters", The Astronomical Journal, 140 (6), ss.1830-1837, arXiv:1008.2755, Bibcode:2010AJ....140.1830G, doi:10.1088/0004-6256/140/6/1830.
Paust, Nathaniel E. Q.; Reid, I. Neill; Piotto, Giampaolo; ve diğerleri. (Şubat 2010), "The ACS Survey of Galactic Globular Clusters. VIII. Effects of Environment on Globular Cluster Global Mass Functions", The Astronomical Journal, 139 (2), ss.476-491, Bibcode:2010AJ....139..476P, doi:10.1088/0004-6256/139/2/476, hdl:2152/34371.
Samus, N. N.; Pastukhova, E. N.; Durlevich, O. V.; Kazarovets, E. V.; Kireeva, N. (2020), "The 83rd Name-List of Variable Stars. Variables in Globular Clusters and Novae", Peremennye Zvezdy (Variable Stars) 40, No. 8, 40 (8), s.8, Bibcode:2020PZ.....40....8S, doi:10.24411/2221-0474-2020-10009
Paust, Nathaniel E. Q.; Reid, I. Neill; Piotto, Giampaolo; ve diğerleri. (Şubat 2010), "The ACS Survey of Galactic Globular Clusters. VIII. Effects of Environment on Globular Cluster Global Mass Functions", The Astronomical Journal, 139 (2), ss.476-491, Bibcode:2010AJ....139..476P, doi:10.1088/0004-6256/139/2/476, hdl:2152/34371.
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"M 13". SIMBAD. Centre de données astronomiques de Strasbourg. Erişim tarihi: 15 Kasım 2006.Arşivlenmesi gereken bağlantıya sahip kaynak şablonu içeren maddeler (link)
"M 13". Messier Objects Mobile -- Charts, Maps & Photos (İngilizce). 16 Ekim 2016. 28 Haziran 2018 tarihinde kaynağından arşivlendi. Erişim tarihi: 23 Nisan 2018.