Παραπομπή APA

Ahmad, F. (1957). Omar: Second Caliph of Islam.

Παραπομπή Chicago Style

Ahmad, Fazl. Omar: Second Caliph of Islam. Shaikh Muhammad Asheaf Lahore, 1957.

Παραπομπή MLA

Ahmad, Fazl. Omar: Second Caliph of Islam. 1957.