Ayano, A., A. Tesfaye, S. Alamirew, and L. Beksisa. “Heterosis and Combining Ability of Coffee Quality Traits in Southwestern Ethiopian Origin Coffee Hybrids”. Ethiopian Journal of Applied Science and Technology, Vol. 9, no. 1, 1, pp. 60 -70, https://ejhs.ju.edu.et/index.php/ejast/article/view/2009.