Dyfyniad APA

Ries, H. (1930). Elementary economic geology. J. Wiley & sons, inc. Chapman & Hall, limited.

Dyfyniad Arddull Chicago

Ries, Heinrich. Elementary Economic Geology. New York, London: J. Wiley & sons, inc. Chapman & Hall, limited, 1930.

Dyfyniad MLA

Ries, Heinrich. Elementary Economic Geology. J. Wiley & sons, inc. Chapman & Hall, limited, 1930.

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