@article{ref1,
title="The place of adjunctive behavior in drug abuse research",
journal="NIDA research monograph",
year="1981",
author="Falk, J. L.",
volume="37",
number="",
pages="271-278",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="1046-9516",
doi="",
url="http://dx.doi.org/"
}