APA استشهاد

Willock, C. (1974). Africa's rift valley. Time-Life Books.

استشهاد بنمط شيكاغو

Willock, Colin. Africa's Rift Valley. Amsterdam: Time-Life Books, 1974.

MLA استشهاد

Willock, Colin. Africa's Rift Valley. Time-Life Books, 1974.