Boke, S. ., and A. . Fekadu. “Lime and NPK Effect on Soil Acidity and Yield of Barley in Different Acid Soils of Southern Region, Ethiopia”. International Journal of Natural Sciences Research, vol. 2, no. 7, July 2014, pp. 113-22, https://archive.conscientiabeam.com/index.php/63/article/view/2323.