1. Benson V, Marano MA. Current estimates from the National Health Interview Survey, 1993. Washington, DC: National Center for Health Statistics, Vital and Health Statistics 10(190), 1994. DHHS Publication No. (PHS) 95–1518
2. Singh GK, Matthews TJ, Clarke SC, et al. Annual summary of births, marriages, divorces, and deaths: United States, 1994; monthly vital statistics report (Vol. 43, No. 13). Hyattsville, MD; National Center for Health Statistics, 1994
3. Morbidity and mortality chartbook on cardiovascular, lung, and blood diseases,1994
4. Pulmonary terms and symbols: a report of the ACCP-ATS Joint Committee on Pulmonary Nomenclature;American College of Chest Physicians, and American Thoracic Society;Chest,1975
5. Prevalence of selected chronic respiratory conditions: United States, 1970;Wilder,1973