Mukhtar, M, R., A. K, M. M.R, N. A.W, A. Y, and A. H. A. Hadi. “Chemical Constituents and Bioactive Compounds of Goniothalumus Tortilipetalus Hend (Annonaceae)”. Malaysian Journal of Science, vol. 19, no. 1, Dec. 2000, pp. 7-12, https://jpmm.um.edu.my/index.php/MJS/article/view/8891.