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.