%0 Journal Article %A Dennis E Doherty %T Documentation of Airflow Obstruction Is Essential to Confirm the Diagnosis of COPD: Are Handheld Spirometers in an Office Setting Valid? %D 2008 %J Respiratory Care %P 429-430 %V 53 %N 4 %U https://rc.rcjournal.com/content/respcare/53/4/429.full.pdf