NGUYEN , . Q. V.; NGO, N. Y. Effect of extraction conditions on total polyphenol content and antioxidant Activity of roselle calyces (hibicus sabdariffa l.) extract. Journal of Technical Education Science, [S. l.], v. 12, n. 3, p. 41–46, 2017. Disponível em: https://www.jte.edu.vn/index.php/jte/article/view/517. Acesso em: 7 apr. 2026.