RT Journal Article SR Electronic T1 Combined Ipratropium and β2-Adrenergic Receptor Agonist in Acute Asthma JF The Journal of the American Board of Family Practice JO J Am Board Fam Med FD American Board of Family Medicine SP 55 OP 65 DO 10.3122/jabfm.13.1.55 VO 13 IS 1 A1 Rex W Force A1 Sheryl J. Herner A1 Terry L. Seaton A1 Marsha K. Mertens YR 2000 UL http://www.jabfm.org/content/13/1/55.abstract AB