3Fonseca W. Risk factors for childhood pneumonia among the urban poor in Fortaleze, Brazil: a casecontrol study. Bulletin of World Health Organization , 1996,74(2) : 199.
4Victora CG. Risk Factors for Deaths due to Respiratory Infections among Brazilian Infants.International Journal of Epidemiology, 1989, 18:918-925.
5Weiss ST. The health effects of involuntary smoking. Am Rev Respir Dis, 1983.128:933.