@article{ref1,
title="The biology of motivation",
journal="Annual review of psychology",
year="1979",
author="Grossman, S. P.",
volume="30",
number="",
pages="209-242",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0066-4308",
doi="10.1146/annurev.ps.30.020179.001233",
url="http://dx.doi.org/10.1146/annurev.ps.30.020179.001233"
}