APA استشهاد

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

استشهاد بنمط شيكاغو

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

MLA استشهاد

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