@article{ref1,
title="Defining insomnia: the role of quantitative criteria",
journal="Sleep",
year="2006",
author="Roth, T. and Drake, C.",
volume="29",
number="4",
pages="424-425",
abstract="<p>[Abstract unavailable]</p> <p>Language: en</p>",
language="en",
issn="0161-8105",
doi="",
url="http://dx.doi.org/"
}