A (sleep routine) can be regular.Logical formLearned from8 sentences. Childhood may undergo sleep.Logical formLearned from8 sentences. Sleep can be altered.Logical formLearned from8 sentences. Symptoms can be constituted-of-or-filled-with sleep.Logical formLearned from8 sentences. Problems can be constituted-of-or-filled-with sleep.Logical formLearned from8 sentences. Studies can be on sleep.Logical formLearned from8 sentences. Sleep can be enough.Logical formLearned from8 sentences. (Sleep disturbance) can be common.Logical formLearned from8 sentences. A (sleep debt) can be accumulated.Logical formLearned from8 sentences. Youth may undergo sleep.Logical formLearned from8 sentences. Sleep may last some hours.Logical formLearned from8 sentences. Depth may pertain-to sleep.Logical formLearned from8 sentences. Sleep can be deep.Logical formLearned from8 sentences. (Sleep signals) may pertain-to a body.Logical formLearned from8 sentences. A person may sleep a big sleep.Logical formLearned from8 sentences.