APA (7th ed.) Citation

Hellen, J. A., & Scargill, D. I. (1976). North Rhine-Westphalia (1. publ., 2. impression.). Oxford Univ. Press.

Chicago Style (17th ed.) Citation

Hellen, John A., and D. I. Scargill. North Rhine-Westphalia. 1. publ., 2. impression. London: Oxford Univ. Press, 1976.

MLA (9th ed.) Citation

Hellen, John A., and D. I. Scargill. North Rhine-Westphalia. 1. publ., 2. impression. Oxford Univ. Press, 1976.