Hartmann, W. (1987). Astronomy the cosmic journey. Wadsworth.
Lua i Stíl Chicago (17ú heag.)Hartmann, William. Astronomy the Cosmic Journey. Belmont, Calif: Wadsworth, 1987.
Lua MLA (9ú heag.)Hartmann, William. Astronomy the Cosmic Journey. Wadsworth, 1987.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.