RT Journal Article SR Electronic T1 Long-term antibiotic therapy reduces exacerbation frequency in patients with COPD but it remains unclear which patients to target JF Evidence Based Medicine JO Evid Based Med FD BMJ Publishing Group Ltd SP 99 OP 99 DO 10.1136/eb-2013-101711 VO 19 IS 3 A1 James P Allinson A1 Gavin C Donaldson YR 2014 UL http://ebm.bmj.com/content/19/3/99.abstract AB