Ndaru, P. H., A. N. Huda, M. Mashudi, and M. Marjuki. “The Effect of Nitrogen Content in Organic Fertilizer on Nutrient Content of Sorghum Hydroponic Fooder”. TERNAK TROPIKA Journal of Tropical Animal Production, vol. 22, no. 2, Dec. 2021, pp. 153-6, https://ternaktropika.ub.ac.id/index.php/tropika/article/view/513.