Cita APA (7a ed.)

Sagan, H. (1992). Introduction to the calculus of variations. Dover.

Cita Chicago Style (17a ed.)

Sagan, Hans. Introduction to the Calculus of Variations. New York: Dover, 1992.

Cita MLA (8a ed.)

Sagan, Hans. Introduction to the Calculus of Variations. Dover, 1992.