APA (7th ed.) Citation

Charroux, R., & Sieveking, O. (1972). The mysterious unknown. Neville Spearman.

Chicago Style (17th ed.) Citation

Charroux, Robert, and Olga Sieveking. The Mysterious Unknown. London: Neville Spearman, 1972.

MLA (9th ed.) Citation

Charroux, Robert, and Olga Sieveking. The Mysterious Unknown. Neville Spearman, 1972.