TRIPATHI, P N, and N L SHARMA. “Evaluation of Pyrite and Gypsum As a Source of Sulphur in Indian Mustard (Brassica Juncea)-Rice (Oryza Sativa) Cropping Sequence”. The Indian Journal of Agricultural Sciences, vol. 64, no. 8, Apr. 2013, https://epubs.icar.org.in/index.php/IJAgS/article/view/29397.