Akiec, N. M. (2000). Geography and environmental studies for the Sudan school certificate. Comboni College.
Citazione stile Chigago Style (17a edizione)Akiec, Nyibong Mayik. Geography and Environmental Studies for the Sudan School Certificate. Khartoum: Comboni College, 2000.
Citatione MLA (9a ed.)Akiec, Nyibong Mayik. Geography and Environmental Studies for the Sudan School Certificate. Comboni College, 2000.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.