Singh, K K, et al. “Improving Productivity and Profitability of Rice ( Oryza Sativa)-Wheat (Triticum Aestivum) Cropping System through Tillage and Planting Management”. The Indian Journal of Agricultural Sciences, vol. 75, no. 7, July 2005, https://epubs.icar.org.in/index.php/IJAgS/article/view/9081.