Sofian-Azirun, M. “Studies on the Acid Phosphatase Activity of the Diamondback Moth, Plutella Xylostella (L) (Lepidoptera: Plutellidae)”. Malaysian Journal of Science, vol. 15, no. 1&2, July 1994, pp. 23-29, http://mojes.um.edu.my/index.php/MJS/article/view/4741.