EICHER, D. L. (1973). Geologic Time Don L. Eicher. Prentice Hall International.
Lua i Stíl Chicago (17ú heag.)EICHER, Don L. Geologic Time Don L. Eicher. Prentice Hall International, 1973.
Lua MLA (8ú heag.)EICHER, Don L. Geologic Time Don L. Eicher. Prentice Hall International, 1973.
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