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 Fayez Kheir A1 Abdul Hamid Alraiyes A1 Daniel Salerno A1 M. Chadi Alraies YR 2013 UL http://www.ccjm.org/content/80/8/500.abstract AB