@article{ref1,
title="Posttraumatic stress disorder: the stressor criterion",
journal="Journal of nervous and mental disease",
year="1987",
author="Ursano, R. J.",
volume="175",
number="5",
pages="273-275",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0022-3018",
doi="",
url="http://dx.doi.org/"
}