- The Historical Geography of Ethiopia: From the First Century AD to 1704 (Fontes Historiae Africanae Series Varia)
- The Southern Nilo-Hamites: East Central Africa Part VIII
- The Nandi of Kenya: Tribal Control in a Pastoral Society
- The Northern Nilo-Hamites: East Central Africa Part VI
- The Prester John of the Indies: A True Relation of the Lands of the Prester John, being the narrative of the Portuguese Embassy to Ethiopia in 1520, ... Volumes I-II