NARAYANA, B SREEMAN, and A SREENIVASA RAJU. “Effect of Source and Level of Sulphur on Yield and Sulphur Content of Plant Parts of Sunflower (Helianthus Annuus)”. The Indian Journal of Agricultural Sciences, vol. 64, no. 3, Apr. 2013, https://epubs.icar.org.in/index.php/IJAgS/article/view/29068.