GUPTA, R. K., SINGH, V., SINGH, Y., SINGH, B., THIND, H. S., KUMAR, A., & VASHISTHA, M. (2011). Need-based fertilizer nitrogen management using leaf colour chart in hybrid rice (Oryza sativa). The Indian Journal of Agricultural Sciences, 81(12). https://epubs.icar.org.in/index.php/IJAgS/article/view/13313