@article{ref1,
title="Contingency management of supplemental drug use during methadone maintenance treatment",
journal="NIDA research monograph",
year="1984",
author="Stitzer, M. L. and Bigelow, G. E. and Liebson, I. A. and McCaul, M. E.",
volume="46",
number="",
pages="84-103",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="1046-9516",
doi="",
url="http://dx.doi.org/"
}