Goldsbury, Ryan; Richer, Harvey B.; Anderson, Jay; Dotter, Aaron; Sarajedini, Ata; Woodley, Kristin (December 2010), ”The ACS Survey of Galactic Globular Clusters. X. New Determinations of Centers for 65 Clusters”, The Astronomical Journal 140 (6): 1830–1837, doi:10.1088/0004-6256/140/6/1830, Bibcode: 2010AJ....140.1830G.
Kharchenko, N. V.; Piskunov, A. E.; Schilbach, E.; Röser, S.; Scholz, R.-D. (2013), ”Global survey of star clusters in the Milky Way. II. The catalogue of basic parameters”, Astronomy and Astrophysics 558: 8, doi:10.1051/0004-6361/201322302, A53, Bibcode: 2013A&A...558A..53K.
Piotto, G.; King, I. R.; Djorgovski, S. G.; Sosin, C.; Zoccali, M.; Saviane, I.; De Angeli, F.; Riello, M.; et al. (September 2002), ”HST color-magnitude diagrams of 74 galactic globular clusters in the HST F439W and F555W bands”, Astronomy and Astrophysics 391 (3): 945–965, doi:10.1051/0004-6361:20020820, Bibcode: 2002A&A...391..945P.
Heasley, J. N.; Janes, K. A.; Zinn, Robert; Demarque, Pierre; Da Costa, Gary S.; Christian, Carol A. (August 2000), ”Hubble Space Telescope Photometry of the Metal-rich Globular Clusters NGC 6624 and NGC 6637”, The Astronomical Journal 120 (2): 879–893, doi:10.1086/301461, Bibcode: 2000AJ....120..879H.
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Goldsbury, Ryan; Richer, Harvey B.; Anderson, Jay; Dotter, Aaron; Sarajedini, Ata; Woodley, Kristin (December 2010), ”The ACS Survey of Galactic Globular Clusters. X. New Determinations of Centers for 65 Clusters”, The Astronomical Journal 140 (6): 1830–1837, doi:10.1088/0004-6256/140/6/1830, Bibcode: 2010AJ....140.1830G.
Kharchenko, N. V.; Piskunov, A. E.; Schilbach, E.; Röser, S.; Scholz, R.-D. (2013), ”Global survey of star clusters in the Milky Way. II. The catalogue of basic parameters”, Astronomy and Astrophysics 558: 8, doi:10.1051/0004-6361/201322302, A53, Bibcode: 2013A&A...558A..53K.
Shapley, Harlow; Sawyer, Helen B. (August 1927), ”A Classification of Globular Clusters”, Harvard College Observatory Bulletin 849 (849): 11–14, Bibcode: 1927BHarO.849...11S.
Mandushev, G.; Staneva, A.; Spasova, N. (December 1991), ”Dynamical masses for galactic globular clusters”, Astronomy and Astrophysics 252: 94, Bibcode: 1991A&A...252...94M.
Piotto, G.; King, I. R.; Djorgovski, S. G.; Sosin, C.; Zoccali, M.; Saviane, I.; De Angeli, F.; Riello, M.; et al. (September 2002), ”HST color-magnitude diagrams of 74 galactic globular clusters in the HST F439W and F555W bands”, Astronomy and Astrophysics 391 (3): 945–965, doi:10.1051/0004-6361:20020820, Bibcode: 2002A&A...391..945P.
Heasley, J. N.; Janes, K. A.; Zinn, Robert; Demarque, Pierre; Da Costa, Gary S.; Christian, Carol A. (August 2000), ”Hubble Space Telescope Photometry of the Metal-rich Globular Clusters NGC 6624 and NGC 6637”, The Astronomical Journal 120 (2): 879–893, doi:10.1086/301461, Bibcode: 2000AJ....120..879H.
