Related Clues:

• ___ cycle
• Radiation dose
• Sleep phase, briefly
• Rock band fronted by Michael Stipe
• Sleep stage abbr.
• Dream state acronym
• Band with the #1 album 'Monster'
• Sleep-clinic study
• Dream letters
• Sleep stage, for short
• Sleep study abbr.
• Sleep lab acronym
• A kind of memory
• Sleep lab study, briefly
• Sleep cycle