APA (7th ed.) Citation

Keynes, J. M., & Keynes, G. (1951). Essays in biography (New ed., with three additional essays.). Hart-Davis.

Chicago Style (17th ed.) Citation

Keynes, John Maynard, and Geoffrey Keynes. Essays in Biography. New ed., with three additional essays. London: Hart-Davis, 1951.

MLA (8th ed.) Citation

Keynes, John Maynard, and Geoffrey Keynes. Essays in Biography. New ed., with three additional essays. Hart-Davis, 1951.