Tamakoshi A, et al. Self-reported sleep duration as a predictor of all-cause mortality: results from the JACC study, Japan. Sleep 2004; 27: 51-54.
Gangwisch JE, et al. Short sleep duration as a risk factor for hypertension: analyses of the first National Health and Nutrition Examination Survey. Hypertension 2006; 47: 833-39.
Ohayon MM, et al. Meta-analysis of quantitative sleep parameters from childhood to old age in healthy individuals: developing normative sleep values across the human lifespan. Sleep 2004; 27: 1255-73.