Ann Ekberg-Jansson, Sven Larsson, Claes-Göran Löfdahl
Ekberg-Jansson A, Larsson S, Löfdahl C.
Preventing exacerbations of chronic bronchitis and COPD
Two recent Cochrane reviews report effective regimens
BMJ 2001; 322 :1259
doi:10.1136/bmj.322.7297.1259