@article{ref1,
title="Steepness of approach and avoidance gradients in humans as a function of experience: Theory and experiment",
journal="Journal of experimental psychology",
year="1965",
author="Epstein, S. and Fenz, W. D.",
volume="70",
number="",
pages="1-12",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0022-1015",
doi="",
url="http://dx.doi.org/"
}