SUWANPAKDEE, S., DIREKBUSARAKOM, S., CHOTIPUNTU, P. and SONGSANGJINDA, P. 2011. Urea as a Nitrogen Source in a Black Tiger Shrimp (Penaeus monodon) Closed Culture System. Walailak Journal of Science and Technology (WJST). 7, 2 (Nov. 2011), 135–140.