SUWANPAKDEE, S., S. DIREKBUSARAKOM, P. CHOTIPUNTU, and P. SONGSANGJINDA. “Urea As a Nitrogen Source in a Black Tiger Shrimp (Penaeus Monodon) Closed Culture System”. Walailak Journal of Science and Technology (WJST), vol. 7, no. 2, Nov. 2011, pp. 135-40, https://wjst.wu.ac.th/index.php/wjst/article/view/37.