W.C, L., A. F, and M. Ali R. “Luteolin and 4-Hydroxybenzoic Acid from the Leaves of Vitex Negundo L”. Malaysian Journal of Science, vol. 24, no. 1, Jan. 2005, pp. 133-5, https://juku.um.edu.my/index.php/MJS/article/view/8946.