APA (7th ed.) Citation

Koestler, A. (1951). The age of longing / by A. Koestler. Collins.

Chicago Style (17th ed.) Citation

Koestler, Arthur. The Age of Longing / by A. Koestler. Collins, 1951.

MLA (9th ed.) Citation

Koestler, Arthur. The Age of Longing / by A. Koestler. Collins, 1951.

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