Dyfyniad APA

Duff, P. (1993). Holmes'principles of Physical Geology, 4th ed. Chapman &Hall.

Dyfyniad Arddull Chicago

Duff, P.McL.D. Holmes'principles of Physical Geology, 4th Ed. London: Chapman &Hall, 1993.

Dyfyniad MLA

Duff, P.McL.D. Holmes'principles of Physical Geology, 4th Ed. Chapman &Hall, 1993.

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