LEVIN, H. L. (1978). The Earter Through Time Harold L. Levin. Saunders College.
Lua i Stíl Chicago (17ú heag.)LEVIN, Harold L. The Earter Through Time Harold L. Levin. Saunders College, 1978.
Lua MLA (8ú heag.)LEVIN, Harold L. The Earter Through Time Harold L. Levin. Saunders College, 1978.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.