EntityQ939906· pop 21· linked from 144 articlespolyphasic sleepSign in to saveany sleep pattern with multiple periods of sleep in a 24-hour periodConnectionssleepwalkingEntityPBSEntityirregular sleep–wake rhythmEntityItalyCountryIndiaCountryChinaCountrySpainCountryGreeceCountryPortugalCountrySouth AfricaCountryPhilippinesCountryCyprusCountryNASAConceptsleepEntityInternational Standard Book NumberEntitydreamEntityIndustrial RevolutionEntitybedEntityhormoneEntitySouthern EuropeEntityCategoriesCircadian rhythmSleep