BABU, SUBHASH, D S RANA, G S YADAV, and M A ANSARI. 2013. “Residual Effect of Sunflower (Helianthus Annuus) Stover and P Management and Direct Effect of N and P on Productivity, Nutrient Uptake and Economics of Spring Sunflower”. The Indian Journal of Agricultural Sciences 83 (3). https://epubs.icar.org.in/index.php/IJAgS/article/view/28340.