Zulamri. “Morning Call of Siamang (Symphalangus Syndactyllus) in Subayang River, Riau – Indonesia”. International Journal of Ecophysiology 1, no. 2 (August 31, 2019): 125-130. Accessed April 23, 2024. https://talenta.usu.ac.id/ijoep/article/view/1275.