1. Chronic lung disease with airflow obstruction—chronic bronchitis and emphysema;Howell,1981
2. Chronic bronchitis, emphysema and airways obstruction;Ingram,1983
3. Chronic obstructive pulmonary diseases;Sherter,1983
4. Acute infections of the lower respiratory tract;Macfarlane,1987
5. Chemotherapy m chronic bronchitis;Francis;Br Med J,1960