Koestler, A., & Butterfield, H. (1964). The sleepwalkers: A history of man's changing vision of the universe. Penguin Books.
Cita Chicago Style (17a ed.)Koestler, Arthur, y Herbert Butterfield. The Sleepwalkers: A History of Man's Changing Vision of the Universe. London: Penguin Books, 1964.
Cita MLA (8a ed.)Koestler, Arthur, y Herbert Butterfield. The Sleepwalkers: A History of Man's Changing Vision of the Universe. Penguin Books, 1964.
Nota: a formatação da citação pode não corresponder 100% ao definido pela respectiva norma.