APA (7th ed.) Citation

Greene, G., & Schmidt, E. (1971). The Heart of the Matter. Penguin Books.

Chicago Style (17th ed.) Citation

Greene, Graham, and Edgar Schmidt. The Heart of the Matter. New York: Penguin Books, 1971.

MLA (9th ed.) Citation

Greene, Graham, and Edgar Schmidt. The Heart of the Matter. Penguin Books, 1971.

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