M.V.S. Naidu*, E. Purandhar and. “Characterization, Classification and Fertility Status of Soils in Semi-Arid Agro-Ecological Region of Puttur Mandal in Chittoor District, Andhra Pradesh”. Journal of the Indian Society of Soil Science, vol. 68, no. 1, Sept. 2020, https://epubs.icar.org.in/index.php/JISSS/article/view/104542.