Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.

APA Citation Edition Citation

Steffen, H. (1975). 1975 Photomap [Jemen]: Approx. 1:25'000; Hayfaan, Al Qubaytah, Yemen Arab Republic. Dept. of geography, Univ..

Chicago Citation Edition Citation

Steffen, Hans. 1975 Photomap [Jemen]: Approx. 1:25'000; Hayfaan, Al Qubaytah, Yemen Arab Republic. Zurich: Dept. of geography, Univ., 1975.

MLA Citation Edition Citation

Steffen, Hans. 1975 Photomap [Jemen]: Approx. 1:25'000; Hayfaan, Al Qubaytah, Yemen Arab Republic. Dept. of geography, Univ., 1975.