Siegel, Michael H.; Dotter, Aaron; Majewski, Steven R.; Sarajedini, Ata; Chaboyer, Brian; Nidever, David L.; Anderson, Jay; Marín-Franch, Antonio; et al. (2007). ”The ACS Survey of Galactic Globular Clusters: M54 and Young Populations in the Sagittarius Dwarf Spheroidal Galaxy”. Astrophysical Journal Letters 667 (1): sid. L57–L60. doi:10.1086/522003. Bibcode: 2007ApJ...667L..57S.
Carretta, E.; Bragaglia, A.; Gratton, R. G.; Lucatello, S.; Bellazzini, M.; Catanzaro, G.; Leone, F.; Momany, Y.; et al. (2010). ”M54 + Sagittarius = ω Centauri”. The Astrophysical Journal Letters 714 (1): sid. L7–L11. doi:10.1088/2041-8205/714/1/L7. Bibcode: 2010ApJ...714L...7C.
Bellazzini, M.; Ibata, R. A.; Chapman, S. C.; Mackey, A. D.; Monaco, L.; Irwin, M. J.; Martin, N. F.; Lewis, G. F.; et al. (2008). ”The Nucleus of the Sagittarius Dsph Galaxy and M54: a Window on the Process of Galaxy Nucleation”. The Astronomical Journal 136 (3): sid. 1147–1170. doi:10.1088/0004-6256/136/3/1147. Bibcode: 2008AJ....136.1147B.
Siegel, Michael H.; Dotter, Aaron; Majewski, Steven R.; Sarajedini, Ata; Chaboyer, Brian; Nidever, David L.; Anderson, Jay; Marín-Franch, Antonio; et al. (2007). ”The ACS Survey of Galactic Globular Clusters: M54 and Young Populations in the Sagittarius Dwarf Spheroidal Galaxy”. Astrophysical Journal Letters 667 (1): sid. L57–L60. doi:10.1086/522003. Bibcode: 2007ApJ...667L..57S.
Carretta, E.; Bragaglia, A.; Gratton, R. G.; Lucatello, S.; Bellazzini, M.; Catanzaro, G.; Leone, F.; Momany, Y.; et al. (2010). ”M54 + Sagittarius = ω Centauri”. The Astrophysical Journal Letters 714 (1): sid. L7–L11. doi:10.1088/2041-8205/714/1/L7. Bibcode: 2010ApJ...714L...7C.
Bellazzini, M.; Ibata, R. A.; Chapman, S. C.; Mackey, A. D.; Monaco, L.; Irwin, M. J.; Martin, N. F.; Lewis, G. F.; et al. (2008). ”The Nucleus of the Sagittarius Dsph Galaxy and M54: a Window on the Process of Galaxy Nucleation”. The Astronomical Journal 136 (3): sid. 1147–1170. doi:10.1088/0004-6256/136/3/1147. Bibcode: 2008AJ....136.1147B.