H. Baumgardt, M. Hilker, A Sollima et A Bellini, « Mean proper motions, space orbits, and velocity dispersion profiles of Galactic globular clusters derived from Gaia DR2 data », Monthly Notices of the Royal Astronomical Societ, vol. 482, no 4, , p. 5138-5155 (DOI10.1093/mnras/sty2997, lire en ligne [PDF])
(en) Carolina Montecinos, S. Villanova, C. Muňoz et C.C. Cortés, « Chemical analysis of the Bulge Globular Cluster NGC 6553 », Monthly Notices of the Royal Astronomical Society, (DOI10.5281/zenodo.2595372, arXiv2103.07014)
H. Baumgardt, M. Hilker, A Sollima et A Bellini, « Mean proper motions, space orbits, and velocity dispersion profiles of Galactic globular clusters derived from Gaia DR2 data », Monthly Notices of the Royal Astronomical Societ, vol. 482, no 4, , p. 5138-5155 (DOI10.1093/mnras/sty2997, lire en ligne [PDF])
J. F. C. Santos Jr. et A. E. Piatti, « Ages and metallicities of star clusters: New calibrations and diagnostic diagrams from visible integrated spectra », Astronomy and Astrophysics, vol. 428, no 1, , p. 79-88 (DOI10.1051/0004-6361:20041560, file:///C:/Users/Donald/OneDrive/AstronomieA/Desktop/PDF%20NGC/Amas_glob%20NGC/Age_MetalGlobClus.pdf [PDF])
(en) Carolina Montecinos, S. Villanova, C. Muňoz et C.C. Cortés, « Chemical analysis of the Bulge Globular Cluster NGC 6553 », Monthly Notices of the Royal Astronomical Society, (DOI10.5281/zenodo.2595372, arXiv2103.07014)