Derso, Tesfamichael Fentie. “An Assessment of Road and Bridge Construction in Simen and Begemider Province, 1963-1991”. Ethiopian Journal of Social Sciences 9, no. 2 (December 23, 2023): 111-132. Accessed September 3, 2025. http://journals.bdu.edu.et/index.php/ejss/article/view/1735.