@article{ref1,
title="Shock facilitation and suppression of alcohol- and coke-maintained behavior",
journal="Psychological reports",
year="1972",
author="Davidson, R. S. and Wallach, E. S.",
volume="31",
number="2",
pages="415-424",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0033-2941",
doi="",
url="http://dx.doi.org/"
}