Nirmalasari, M. A. Y., and Y. Y. Bolly. “The Booklet Development of Inorganic Fertilization System Based on Problem”. Jurnal Akademika Kimia, vol. 9, no. 4, Nov. 2020, pp. 230-6, doi:10.22487/j24775185.2020.v9.i4.pp230-236.