@article{ref1,
title="Statistical Analysis on Energy Field of Seismicity in Ningxia and Its Neighborhood Region",
journal="Acta seismologica sinica. English edition",
year="2004",
author="Yang, MZ and Zhao, WM",
volume="17",
number="5",
pages="571-",
abstract="<p>[Abstract unavailable]</p>",
language="",
issn="1000-9116",
doi="",
url="http://dx.doi.org/"
}