"Bodyrhythms: Chronobiology and Peak Performance" Lynne Lamberg (William Morrow and Company, Inc., 1994)
"No More Sleepless Nights" Peter Hauri, Pill, and Shirley Linde, Pill (John Wiley and Sons, Inc. 1990) "Encyclopedia of Sleep and Dreaming" Edited by Mary A. Caskadon, Pill (New York: Macmillan, 1992)