A. Hadi, A. H., M. ’ Ropi Mukhtar, K. ’ Choon Wee, and S. S. Syed Abd. Azziz. “Alkaloids Isolated from Dehaasia Candolleana (Meisn.) Kosterm”. Malaysian Journal of Science, vol. 27, no. 2, Aug. 2008, pp. 115-21, http://ojie.um.edu.my/index.php/MJS/article/view/9273.