University College of Addis Ababa. Geophysical Observatory & Haile Sellassie I University. Geophysical Observatory. (1959). Bulletin of the Geophysical Observatory. University College Press.
Chicago-referens (17:e uppl.)University College of Addis Ababa. Geophysical Observatory och Haile Sellassie I University. Geophysical Observatory. Bulletin of the Geophysical Observatory. Addis Ababa: University College Press, 1959.
MLA-referens (8:e uppl.)University College of Addis Ababa. Geophysical Observatory och Haile Sellassie I University. Geophysical Observatory. Bulletin of the Geophysical Observatory. University College Press, 1959.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.