1. Higgins ITT. Epidemiology of bronchitis and emphysema. In: Fishman AP, (ed.) Pulmonary Diseases and Disorders. 2nd Edition. New York; McGraw-Hill, 1988.
2. Higgins MW. Chronic-airways disease in the United States: trends and determinants. Chest 1989; 96 (Suppl.): 328s-334s.
3. Kinsman RA, Yaroush RA, Fernandez RA, Dirks JF, Schnocket M, Fukuhara J. Symptoms and experiences in chronic bronchitis and emphysema. Chest 1983: 5: 755?761.
4. Bergner M, Bobbitt RA, Carter WB, Gilson BS. The sickness impact profile: Development and final revision of a health status measure. Med Care 1981; 19: 787?786.
5. McSweeney AJ, Labuhn KT. Chronic obstructive pulmonary disease. In: Spilker B, Ed. Quality of Life Assessment in Clinical Trials. New York: Raven Press, 1990; 391?417.