Last August,a study in the journal Sleep Medicine said children who go to bed after nine o'clock took longer to fall asleep and slept less.
VOA: special.2010.06.09
It said they were getting far less sleep than they should.
VOA: special.2009.06.02
The mice with the mutation needed less sleep than normal mice.
VOA: special.2009.08.26
People who have this mutation need less sleep than others.
VOA: special.2009.08.26
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