Arda Meylia, Safira, dan Abdul Haris Mustari. “Distribution, Population, and Habitat of Siamang (Symphalangus Syndactylus) in Bulu Mario, South Tapanuli”. Jurnal Penelitian Hutan Dan Konservasi Alam, vol. 19, no. 1, Juni 2022, hlm. 101-18, https://ejournal.aptklhi.org/index.php/JPHKA/article/view/616.