RT Journal Article SR Electronic T1 Lung air-fluid level in a smoker JF Cleveland Clinic Journal of Medicine JO Cleve Clin J Med FD Cleveland Clinic SP 500 OP 501 DO 10.3949/ccjm.80a.12107 VO 80 IS 8 A1 Kheir, Fayez A1 Alraiyes, Abdul Hamid A1 Salerno, Daniel A1 Alraies, M. Chadi YR 2013 UL http://www.ccjm.org/content/80/8/500.abstract AB