RT Journal Article SR Electronic T1 Management of difficult asthma JF Cleveland Clinic Journal of Medicine JO Cleve Clin J Med FD Cleveland Clinic SP 33 OP 38 VO 47 IS 1 A1 Ahmad, Muzaffar A1 Golish, Joseph A. YR 1980 UL http://www.ccjm.org/content/47/1/33.abstract AB