<http://schema.org/description>
"Every animal sleeps -- some more than others -- but why they do it is a mystery to scientists. Is sleep more than just beauty rest? Could skimping on it kill you? And how much do you really need?"^^<http://www.w3.org/2001/XMLSchema#string>
<http://science.howstuffworks.com/life/inside-the-mind/human-brain/sleep1.htm>