Somboun Khantivong. (1997) Population policy options for Lao PDR. Mahidol University,:ม.ป.ท.Somboun Khantivong. 1997. Population policy options for Lao PDR. ม.ป.ท.:Mahidol University,;Somboun Khantivong. Population policy options for Lao PDR. ม.ป.ท.:Mahidol University, 1997. Print.