Deep Sleep 101, by Gregg Jacobs. (Blue Marble, 2001, 52 pp plus music CD, $23.95.). Author Gregg Jacobs, offers a concise guidebook of ways to improve sleep.
"Temporally structured replay of awake hippocampal ensemble activity during rapid eye movement sleep," by Kenway Louie and Matthew A. Wilson. (Neuron, January 2001, Volume 29, pp. 145-156.)
"Sleep, learning, and dreams: off-line memory reprocessing," by Robert Stickgold, et al. (Science, November 2, 2001, Volume 294, pp. 1052-1057.)
This educational, non-commercial site is devoted to improving sleep health and bills itself as a source of "everything you wanted to know about sleep but were too tired to ask."
National Center on Sleep Disorders Research
This web site posted by the National Institutes of Health includes patient information on sleep and sleep disorders.