Elizabeth Koshy, B., O. Selvaraj, and M. Sekaran. “Variation in Meristic Characters of Four Strains of Malaysian Freshwater Angelfish Pterophyllum Scalare (L.)”. Malaysian Journal of Science, vol. 27, no. 1, Apr. 2008, pp. 69-73, https://juku.um.edu.my/index.php/MJS/article/view/7934.