Rashwan, B. R. A., and A. E. A. Shaheen. “The Impact of Potassium Sources and Bio Fertilizer on Corn Plant and Potassium Availability in Calcareous Soil”. Asian Soil Research Journal, Vol. 5, no. 1, Mar. 2021, pp. 27-37, doi:10.9734/asrj/2021/v5i130099.