PT - JOURNAL ARTICLE AU - Jane Kirkby AU - Raffaella Nenna AU - Aisling McGowan TI - Changes in FEV<sub>1</sub> over time in COPD and the importance of spirometry reference ranges: the devil is in the detail AID - 10.1183/20734735.0252-2019 DP - 2019 Dec 01 TA - Breathe PG - 337--339 VI - 15 IP - 4 4099 - http://breathe.ersjournals.com/content/15/4/337.short 4100 - http://breathe.ersjournals.com/content/15/4/337.full SO - Breathe2019 Dec 01; 15