Eggen, O.J.; Lynden-Bell, D.; Sandage, A. R. (1962). “Evidence from the motions of old stars that the Galaxy collapsed”. The Astrophysical Journal136: 748. Bibcode: 1962ApJ...136..748E. doi:10.1086/147433.
Searle, L.; Zinn, R. (1978). “Compositions of halo clusters and the formation of the galactic halo”. The Astrophysical Journal225: 357–379. Bibcode: 1978ApJ...225..357S. doi:10.1086/156499.
Eggen, O.J.; Lynden-Bell, D.; Sandage, A. R. (1962). “Evidence from the motions of old stars that the Galaxy collapsed”. The Astrophysical Journal136: 748. Bibcode: 1962ApJ...136..748E. doi:10.1086/147433.
Searle, L.; Zinn, R. (1978). “Compositions of halo clusters and the formation of the galactic halo”. The Astrophysical Journal225: 357–379. Bibcode: 1978ApJ...225..357S. doi:10.1086/156499.