R. N. PANDEY and B. H. GIRISH, “Evaluation of some extractants for predicting soil sulphur availability to cowpea (Vigna unguiculata)”, Indian J Agri Sci, vol. 76, no. 3, Jan. 2011, Accessed: May 21, 2025. [Online]. Available: https://epubs.icar.org.in/index.php/IJAgS/article/view/2678