Elida Purba, Chairul Umam, Azhar,. “The Rheological Characteristics of Dammar Mata Kuching”. Journal of Engineering and Scientific Research 2, no. 2 (December 28, 2020): 97–101. Accessed January 15, 2026. https://www.jesr.eng.unila.ac.id.121-50-32-50.cpanel.site/index.php/ojs/article/view/50.