Salpeter, E. E. (1981). Galaxies, clusters and invisible mass. Zenodo.
Cita Chicago (17th ed.)Salpeter, Edwin E. Galaxies, Clusters and Invisible Mass. Zenodo, 1981.
Cita MLA (9th ed.)Salpeter, Edwin E. Galaxies, Clusters and Invisible Mass. Zenodo, 1981.
Atenció: Aquestes cites poden no estar 100% correctes.