Sah, G., et al. “Effects of Tillage and Crop Establishment Methods, Crop Residues, and Nitrogen Levels on Wheat Productivity, Energy-Savings and Greenhouse Gas Emission under Rice -Wheat Cropping System”. Nepal Journal of Science and Technology, vol. 15, no. 2, Feb. 2015, pp. 1-10, doi:10.3126/njst.v15i2.12104.