3Owayed AF, Campbell DM, Wang EE. Underlying causes of recurrent pneumonia in children. Arch Pediatr Adolesc Med, 2000,154 : 190-194.
4Ciftci E, Gunes M, Koksal Y, et al. Underlying causes of recurrent pneumonia in Turkish children in a university hospital. J Trap Pediatr, 2003, 49:212-215.
5Adam KA. Persistent or recurrent pneumonia in Saudi children seen at King Khalid University Hospital, Riyadh: clinical profile and some predisposing factors. Ann Trop Paediatr, 1991,11 : 129- 135.
6Lodha R. Recurrent pneumonia in children: clinical profile and underlying cause. Acta Paediatria, 2002,91 : 1170-1173.
7David V, Katkin JP. Chronic and recurrent pneumonias in children. Semin Respir Infect,2002,17:72-84.