Wanachiwanawin, D., Junnoo, V., Ongrotchanakun, J., Kaewmanee, S., Punthuprapasa, P., Yoolek, A., Suvuttho, S., Monkong, N., Lertlaituan, P. and Patharangura, W. 1999. Prevalence of Parasitic Infections in Thai Workers from 1993 to 1997. Siriraj Medical Journal. 51, 4 (Apr. 1999), 225–231.