Dyfyniad APA

U.S. Geological Survey, U. (1971). American Mineralogist, vol.56, (1-12).

Dyfyniad Arddull Chicago

U.S. Geological Survey, U.S.A. American Mineralogist, Vol.56, (1-12). U.S. Geological Survey, U.S.A, 1971.

Dyfyniad MLA

U.S. Geological Survey, U.S.A. American Mineralogist, Vol.56, (1-12). 1971.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.