Ali และ Zulfiqar. (1991) Factors affecting the occurrence of acute respiratory tract intection in children under five years of age. Mahidol University,:ม.ป.ท.Ali และ Zulfiqar. 1991. Factors affecting the occurrence of acute respiratory tract intection in children under five years of age. ม.ป.ท.:Mahidol University,;Ali และ Zulfiqar. Factors affecting the occurrence of acute respiratory tract intection in children under five years of age. ม.ป.ท.:Mahidol University, 1991. Print.