“El Nino Effect on Coffee Growth and Productivity on Several Agroforestry Systems in Gumitir Mountain Coffee Farms, East Java, Indonesia”, PP, vol. 33, no. 3, pp. 168–179, Dec. 2017, Accessed: May 01, 2026. [Online]. Available: https://www.ccrjournal.com/index.php/ccrj/article/view/