Maitra, D N, et al. “Effect of Phosphorous and Farmyard Manure Applied to Sunnhemp (Crotalaria Juncea) on Yield and Nutrient Uptake of Sunnhemp- Wheat (Triticum Aestivum) Cropping System and Fertility Status in Typic Ustocrept of Uttar Pradesh”. The Indian Journal of Agricultural Sciences, vol. 78, no. 1, Jan. 2008, https://epubs.icar.org.in/index.php/IJAgS/article/view/9771.