M. Hailu and K. Michael, “Effectiveness of Summer Upgrading Teachers’ Education Program of Primary Schools in Tigray Regional State”, IJSBAR, vol. 42, no. 1, pp. 124–150, Oct. 2018, Accessed: Sep. 11, 2025. [Online]. Available: https://gssrr.org/JournalOfBasicAndApplied/article/view/9242