@article{ref1,
title="Why are there so many threat displays?",
journal="Journal of theoretical biology",
year="1980",
author="Andersson, M.",
volume="86",
number="4",
pages="773-781",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0022-5193",
doi="",
url="http://dx.doi.org/"
}