Selection criteria and external validity.
Kozma
C M
CM
Strategic Outcomes Services, Inc., Research Triangle Park, North Carolina, USA.
D006302:Health Services Research / Q000379:methods*; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000188:drug therapy; D017063:Outcome Assessment, Health Care; D010343:Patient Admission / Q000706:statistics & numerical data; D018579:Patient Selection; D015203:Reproducibility of Results; D014481:United States