Hermawan, Agus, Adipati Napoleon, and Bakri Bakri. “Physical Properties of Briquette Fertilizers Made from Urea and Fly Ash-Azolla”. JOURNAL OF TROPICAL SOILS 23, no. 3 (March 22, 2019): 143–150. Accessed July 29, 2025. https://journal.unila.ac.id/index.php/tropicalsoil/article/view/282.