Le Bas, M.J.; Mohr, P.A. (1968). "Feldspathoidal rocks from the Cainozoic volcanic province of Ethiopia". Geologische Rundschau. 58 (1): 273–280. doi:10.1007/BF01820608.
Miruts Hagos; Koeberl, C.; Jourdan, F. (2017). "Geochemistry and Geochronology of Phonolitic and Trachytic Source Rocks of the Axum Obelisks and Other Stone Artifacts, Axum, Ethiopia". Geoheritage. 9 (4): 479–494. doi:10.1007/s12371-016-0199-7.
Machado, M.J. (2015). Geomorphology of the Adwa District. In Landscapes and Landforms of Ethiopia. Dordrecht: Springer. pp. 163–178. doi:10.1007/978-94-017-8026-1_8.
