APA (7th ed.) Citation

Sommerfeld, A. (1969). Lectures on theoretical physics.

Chicago Style (17th ed.) Citation

Sommerfeld, Arnold. Lectures on Theoretical Physics. New York, 1969.

MLA (9th ed.) Citation

Sommerfeld, Arnold. Lectures on Theoretical Physics. 1969.

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