1. Nyx;Leadbetter,1999
2. What is sleep? The book of the sandman and the alphabet of sleep;Poortviliet,1989
3. Lucretius: on the nature of things;Rouse,1992
4. Physiology of sleep: on wakefulness;Hammond,1866
5. Sleep as a problem of localization;von Economo;J Nerv Ment Dis,1930