R, Vasundhara, et al. “Spatial Assessment of Soil Fertility Status in Shiratti Sub Watershed of Semi-Arid Tropics in Southern India”. International Journal of Bio-Resource and Stress Management, vol. 11, no. Apr, 2, Apr. 2020, pp. 163-70, https://ojs.pphouse.org/index.php/IJBSM/article/view/3997.