VENUGOPALAN, M V, and D BLAISE. “Effect of Planting Density and Nitrogen Level on Canopy Spectral Reflectance and Productivity of Upland Cotton (Gossypium hirsutum)*”. The Indian Journal of Agricultural Sciences, vol. 71, no. 9, Apr. 2014, https://epubs.icar.org.in/index.php/IJAgS/article/view/40248.