Michael M. Shara, S. Michael Fall, R. Michael Rich et David Zurek, «Hubble Space Telescope Observations of NGC 121: First Detection of Blue Stragglers in an Extragalactic Globular Cluster», The Astrophysical Journal, vol.508, no2, , p.570-575 (DOI10.1086/306423, lire en ligne[PDF]).
E. Dalessandro, E. Lapenna, A. Mucciarelli, L. Origlia, F. R. Ferraro et B. Lanzoni, «MULTIPLE POPULATIONS IN THE OLD AND MASSIVE SMALL MAGELLANIC CLOUD GLOBULAR CLUSTER NGC 121», The Astrophysical Journal, vol.829, no2, , p.8 pages (DOI10.3847/0004-637X/829/2/77, lire en ligne[PDF]).
Michael M. Shara, S. Michael Fall, R. Michael Rich et David Zurek, «Hubble Space Telescope Observations of NGC 121: First Detection of Blue Stragglers in an Extragalactic Globular Cluster», The Astrophysical Journal, vol.508, no2, , p.570-575 (DOI10.1086/306423, lire en ligne[PDF]).
E. Dalessandro, E. Lapenna, A. Mucciarelli, L. Origlia, F. R. Ferraro et B. Lanzoni, «MULTIPLE POPULATIONS IN THE OLD AND MASSIVE SMALL MAGELLANIC CLOUD GLOBULAR CLUSTER NGC 121», The Astrophysical Journal, vol.829, no2, , p.8 pages (DOI10.3847/0004-637X/829/2/77, lire en ligne[PDF]).