@article{ref1,
title="Clustering",
journal="Annual review of biophysics and bioengineering",
year="1973",
author="Hartigan, J. A.",
volume="2",
number="",
pages="81-101",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0084-6589",
doi="10.1146/annurev.bb.02.060173.000501",
url="http://dx.doi.org/10.1146/annurev.bb.02.060173.000501"
}