SUGARDJITO, JITO. “USE OF FOREST STRATA BY THE SUMATRAN ORANG-UTANS: A CONSIDERATION OF FUNCTIONAL ASPECTS”. Treubia 29, no. 4 (January 12, 2016): 255–265. Accessed December 6, 2025. https://ejournal.brin.go.id/treubia/article/view/9525.