APA (7th ed.) Citation
Sommerfeld, A. (1950). Lectures on theoretical physics. Academic Press.
Chicago Style (17th ed.) Citation
Sommerfeld, Arnold. Lectures on Theoretical Physics. New York: Academic Press, 1950.
MLA (9th ed.) Citation
Sommerfeld, Arnold. Lectures on Theoretical Physics. Academic Press, 1950.
Warning: These citations may not always be 100% accurate.