Razak, Abdul, and Des M. “Iridology Method for Detecting Effect of Water Quality and Stress in Fish”. Science and Environmental Journal for Postgraduate 1, no. 1 (January 7, 2019): 11-16. Accessed December 3, 2021. http://senjop.ppj.unp.ac.id/index.php/senjop/article/view/14.