RAMESH, P, et al. “Response of Pigeonpea (Cajanus Cajan) Varieties to Organic Manures and Their Influence on Fertility and Enzyme Activity of Soil*”. The Indian Journal of Agricultural Sciences, vol. 76, no. 4, Jan. 2011, https://epubs.icar.org.in/index.php/IJAgS/article/view/2744.