C. M. Zhen, M.F. Mohd Amin, S. Onsanit, M. S. M. Rasat, N. H. Abdullah, T.C. Ling, K.N.S.W.S. Wong, N. Adnan, N.J. Ramli. “Correlation of Dissolved Oxygen and Nitrate in Aquaculture Pond Integrated Sensor System ”. International Journal of Advanced Science and Technology, Vol. 29, no. 5s, May 2020, pp. 1986 -92, http://sersc.org/journals/index.php/IJAST/article/view/17916.