Spencer, E. W. (1962). Basic concepts of physical geology. Oxford.
Cita Chicago (17th ed.)Spencer, Edgar Winston. Basic Concepts of Physical Geology. New Delhi: Oxford, 1962.
Cita MLA (9th ed.)Spencer, Edgar Winston. Basic Concepts of Physical Geology. Oxford, 1962.
Atenció: Aquestes cites poden no estar 100% correctes.