Press, F., & Siever, R. (1998). Understanding earth (2nd ed.). New York: W. H. Freeman and Company.
Παραπομπή Chicago StylePress, Frank, and Raymond Siever. Understanding Earth. 2nd ed. New York: W. H. Freeman and Company, 1998.
Παραπομπή MLAPress, Frank, and Raymond Siever. Understanding Earth. 2nd ed. New York: W. H. Freeman and Company, 1998.
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