Sirappa, Marthen Pasang, and Max Leovold Jhon Titahena. “Improvement of Suboptimal Land Productivity Approach by Land and Plant Management”. JOURNAL OF TROPICAL SOILS 19, no. 2 (April 21, 2015): 99–109. Accessed August 10, 2025. https://journal.unila.ac.id/index.php/tropicalsoil/article/view/207.