@article{ref1,
title="How many great earthquakes should we expect?",
journal="Proceedings of the National Academy of Sciences of the United States of America",
year="2012",
author="Beroza, Gregory C.",
volume="109",
number="3",
pages="651-652",
abstract="<p>[Abstract unavailable]</p> <p>Language: en</p>",
language="en",
issn="0027-8424",
doi="10.1073/pnas.1120744109",
url="http://dx.doi.org/10.1073/pnas.1120744109"
}