@article{ref1,
title="Selection biases in sociological data",
journal="Social science research",
year="1982",
author="Berk, Richard A. and Ray, Subhash C.",
volume="11",
number="4",
pages="352-398",
abstract="<p>[Abstract unavailable]</p>",
language="en",
issn="0049-089X",
doi="10.1016/0049-089X(82)90003-5",
url="http://dx.doi.org/10.1016/0049-089X(82)90003-5"
}