1. US Department of Health and Human Services, National Center on Sleep Disorders Research. 2003 National Sleep Disorders Research Plan. Available at http://www.nhlbi.nih.gov/health/prof/sleep/res_plan/sleep-rplan.pdf
2. QuickStats: Percentage of Adults Aged ≥ 18 Years Who Reported an Average of ≤ 6 Hours of Sleep per 24-Hour Period, by Sex and Age Group --- National Health Interview Survey, United States, 1985 and 2006;Centers for Disease Control and Prevention.;MMWR,2008
3. National Sleep Foundation. 2008 Sleep in America Poll: Summary of Findings. Available at http://www.sleepfoundation.org/atf/cf/%7Bf6bf2668-alb4-4fe8-8dla-a5d39340d9cb%7D/2008%20POLL%20SOF.PDF
4. Bureau of Labor Statistics. American Time Use Survey—2006 Results. Available at http://www.bls.gov/news.release/pdf/atus.pdf
5. Some preliminary findings on physical complaints from a prospective study of 1,064,004 men and women,1964