Suraphong Wattanachira และ Suthirak Sujarittanonta. (1983) The combined effects of lead and zinc on the completely mixed activated sludge proccess. Chulalongkorn University.:ม.ป.ท.Suraphong Wattanachira และ Suthirak Sujarittanonta. 1983. The combined effects of lead and zinc on the completely mixed activated sludge proccess. ม.ป.ท.:Chulalongkorn University.;Suraphong Wattanachira และ Suthirak Sujarittanonta. The combined effects of lead and zinc on the completely mixed activated sludge proccess. ม.ป.ท.:Chulalongkorn University. 1983. Print.