International Journal of COPD · 2010 · 116 citations · 39 references
Most patients with COPD suffer disturbed sleep. Sleep quality was correlated with general and disease-specific quality of life. Only a minority of COPD patients complain of being sleepy.
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Coefficient Alpha and the Internal Structure of Tests
Lee J. Cronbach · Psychometrika · 1951 · 42.3K citations · Full text
A New Method for Measuring Daytime Sleepiness: The Epworth Sleepiness Scale
Murray W. Johns · SLEEP · 1991 · 16.8K citations · Full text
1994 · 9.4K citations