@article{ref1,
title="The Classification of Social Phenomena, II",
journal="American journal of sociology",
year="1911",
author="Hayes, Edward C.",
volume="17",
number="2",
pages="188-205",
abstract="<p>[Abstract unavailable]</p>",
language="",
issn="0002-9602",
doi="10.1086/211964",
url="http://dx.doi.org/10.1086/211964"
}