APA (7th ed.) Citation

Sontag, S. (2003). Regarding the pain of others. Penguin Books.

Chicago Style (17th ed.) Citation

Sontag, Susan. Regarding the Pain of Others. London: Penguin Books, 2003.

MLA (9th ed.) Citation

Sontag, Susan. Regarding the Pain of Others. Penguin Books, 2003.