American Psychological Association. (2006). Why sleep is important and what happens when you don't get enough. Retrieved October 3, 2006, from www.apa.org/topics/whysleep.html.
2.
ColtenH. R.AltevogtB. M. (Eds.) for Institute of Medicine. (2006). Sleep disorders and sleep deprivation: An unmet public health problem. Washington, DC: National Academies Press.
3.
CzeislerC. A.FryerB. (2006). Sleep deficit: The performance killer. A conversation with Harvard Medical School professor Charles A. Czeisler [Electronic version]. Harvard Business Review, 84(10), 53–59.
4.
RussoM. B. (2006). Normal sleep, sleep physiology, and sleep deprivation: General principles. Retrieved September 27, 2006, from www.emedicine.com/neuro/topic444.htm.