University College of Addis Ababa. Geophysical Observatory & Haile Sellassie I University. Geophysical Observatory. (1959). Bulletin of the Geophysical Observatory. University College Press.
Παραπομπή σε μορφή Chicago (17η εκδ.)University College of Addis Ababa. Geophysical Observatory και Haile Sellassie I University. Geophysical Observatory. Bulletin of the Geophysical Observatory. Addis Ababa: University College Press, 1959.
Παραπομπή σε μορφή MLA (8th εκδ.)University College of Addis Ababa. Geophysical Observatory και Haile Sellassie I University. Geophysical Observatory. Bulletin of the Geophysical Observatory. University College Press, 1959.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.