Syed Abd. Aziz, S. S., M. R. Mukhtar, A. H. A. Hadi, N. R. Abdullah, and K. Awang. “Isoquinoline Alkaloids and Antimalarial Properties of Popowia Perakensis Extract”. Journal of Science and Mathematics Letters, vol. 1, no. 2, Dec. 2009, pp. 80-86, https://ejournal.upsi.edu.my/index.php/JSML/article/view/382.