@article{ref1,
title="States and Nations as Challenges to Peace Research",
journal="Journal of peace research",
year="1991",
author="Wiberg, Hakan",
volume="28",
number="4",
pages="337-343",
abstract="<p>[Abstract unavailable]</p>",
language="",
issn="0022-3433",
doi="10.1177/0022343391028004001",
url="http://dx.doi.org/10.1177/0022343391028004001"
}