Felicia, F., E. Girsang, A. N. Nasution, and I. N. Ehrich Liester. “Potential ABTS Reducing and Anti-Collagenase Activity of Scutellarein and Apigenin”. American Scientific Research Journal for Engineering, Technology, and Sciences, vol. 57, no. 1, July 2019, pp. 124-30, https://asrjetsjournal.org/index.php/American_Scientific_Journal/article/view/4906.