@article{ref1,
title="What causes post-traumatic stress disorder: two views",
journal="Harvard Mental Health Letter",
year="2002",
author="",
volume="19",
number="4",
pages="8-8",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="1057-5022",
doi="",
url="http://dx.doi.org/"
}