Soemarjono, E. “Strategi Pengembangan Kopi Robusta Rakyat Di Kabupaten Bondowoso”. FORAGRI : Jurnal Ilmu Pertanian, vol. 1, no. 1, Apr. 2021, pp. 37-49, https://journal.unibo.ac.id/index.php/foragri/article/view/17.