APA (7th ed.) Citation

Sagan, H. (1993). Introduction to the calculus of variations (Unabridged Dover republ. [der Ausg.] New York 1969.). Dover Publ.

Chicago Style (17th ed.) Citation

Sagan, Hans. Introduction to the Calculus of Variations. Unabridged Dover republ. [der Ausg.] New York 1969. New York: Dover Publ, 1993.

MLA (9th ed.) Citation

Sagan, Hans. Introduction to the Calculus of Variations. Unabridged Dover republ. [der Ausg.] New York 1969. Dover Publ, 1993.