APA استشهاد

Logan, J. D. (1977). Invariant variational principles. Academic press.

استشهاد بنمط شيكاغو

Logan, John David. Invariant Variational Principles. New York: Academic press, 1977.

MLA استشهاد

Logan, John David. Invariant Variational Principles. Academic press, 1977.