Παραπομπή APA

Duff, P. M. D. (1992). Holmes' Principles of physical geology (4th ed.). ELBS with chapman & hall.

Παραπομπή Chicago Style

Duff, P Mcl D. Holmes' Principles of Physical Geology. 4th ed. London: ELBS with chapman & hall, 1992.

Παραπομπή MLA

Duff, P Mcl D. Holmes' Principles of Physical Geology. 4th ed. ELBS with chapman & hall, 1992.