TY - JOUR T1 - Exacerbations of chronic obstructive pulmonary disease: definition, aetiology and management JF - Clinical Medicine JO - Clin Med SP - 170 LP - 173 DO - 10.7861/clinmedicine.9-2-170 VL - 9 IS - 2 AU - Irem Patel Y1 - 2009/04/01 UR - http://www.rcpjournals.org/content/9/2/170.abstract ER -