“Effects of Morphological Age and Indole-3-Butyric Acid Concentration on Rooting of Selected Robusta Coffee Varieties”. Pelita Perkebunan (a Coffee and Cocoa Research Journal) 41, no. 3 (December 31, 2025): 280–296. Accessed May 25, 2026. https://ccrjournal.com/index.php/ccrj/article/view/698.