W.L, Chu, Ramadhona M.S, and Phang S.M. 2007. “Assessment of Three Tropical Chlorophytes As Bioassay Organisms for Nitrogen and Phosphorus Enrichment in Freshwater Ecosystems”. Malaysian Journal of Science 26 (2):27-39. https://juku.um.edu.my/index.php/MJS/article/view/8051.