Pranata, A. J., & Simanjuntak, B. H. (2020). The Effect of Using Leonardite Mainic Acid as Urea Coater on The Growth And Yield Of Corn (Zea mays). Gontor Agrotech Science Journal, 6(1), 17–33. https://doi.org/10.21111/agrotech.v6i1.3593