Firmansyah, Erick, and Arif Umami. “Potential of Intercropping of Oil Palm (E. Guineensis Jacq.) and Liberica Coffee (C. Liberica L.): A Case Study in Smallholder Plantation”. Journal of Applied Agricultural Science and Technology 5, no. 2 (August 31, 2021): 106-116. Accessed May 3, 2024. http://jaast.org/index.php/jaast/article/view/22.