Johnson, R. B., DeGraff, J. V., & DeGraff, J. V. (1988). Principles of engineering geology. New York: Wiley.
Παραπομπή Chicago StyleJohnson, Robert Britten, Jerome V. DeGraff, and Jerome V. DeGraff. Principles of Engineering Geology. New York: Wiley, 1988.
Παραπομπή MLAJohnson, Robert Britten, Jerome V. DeGraff, and Jerome V. DeGraff. Principles of Engineering Geology. New York: Wiley, 1988.
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