Citazione Stile APA (7a Edizione)

Levin, H. L. (1999). The earth through time (6th ed.). Saunders College Pub.

Citazione stile Chigago Style (17a edizione)

Levin, Harold L. The Earth Through Time. 6th ed. Fort Worth: Saunders College Pub, 1999.

Citatione MLA (9a ed.)

Levin, Harold L. The Earth Through Time. 6th ed. Saunders College Pub, 1999.