APA (7th ed.) Citation

Fox, C. (1950). An introduction to the calculus of variations. Oxford Univ. Press.

Chicago Style (17th ed.) Citation

Fox, Charles. An Introduction to the Calculus of Variations. London: Oxford Univ. Press, 1950.

MLA (9th ed.) Citation

Fox, Charles. An Introduction to the Calculus of Variations. Oxford Univ. Press, 1950.

Warning: These citations may not always be 100% accurate.