Não informado. (1959). Bulletin of the Geophysical Observatory. Haile Selassie i University.
Style de citation Chicago (17e éd.)Não informado. Bulletin of the Geophysical Observatory. Addis Ababa: Haile Selassie i University, 1959.
Style de citation MLA (8e éd.)Não informado. Bulletin of the Geophysical Observatory. Haile Selassie i University, 1959.
Attention : ces citations peuvent ne pas être correctes à 100%.