title: Patterns and duration of sleep in permanent security night guards.
mesh_terms: D000328:Adult; D000368:Aged; D002940:Circadian Rhythm; D006801:Humans; D008875:Middle Aged; D010865:Pilot Projects; D012637:Security Measures; D012890:Sleep / Q000502:physiology*; D014937:Work; D014940:Work Schedule Tolerance