SINGH, KALYAN, et al. “Effect of Age of Seedling and Spacing on Yield, Economics, Soil Health and Digestibility of Rice (Oryza Sativa) Genotypes under System of Rice Intensification”. The Indian Journal of Agricultural Sciences, vol. 83, no. 5, May 2013, https://epubs.icar.org.in/index.php/IJAgS/article/view/29629.