Dhianawaty, D., and R. Panigoro. “Antioxidant Activity and Total Weight of Carotenoids in Red Sweet Potato (Ipomoea Batatas L.) Tuber”. International Journal of Research in Phytochemistry and Pharmacology, Vol. 3, no. 1, Feb. 2013, pp. 70-73, https://scienztech.org/index.php/ijrpp/article/view/846.