APA (7th ed.) Citation

Simenon, G. (1965). The blue room: Georges Simenon. Penguin Books.

Chicago Style (17th ed.) Citation

Simenon, Georges. The Blue Room: Georges Simenon. London: Penguin Books, 1965.

MLA (9th ed.) Citation

Simenon, Georges. The Blue Room: Georges Simenon. Penguin Books, 1965.