@article{ref1,
title="PERCEPTION OF SLANTED SURFACES: Monograph Supplement 2",
journal="Perceptual and motor skills",
year="1956",
author="Gruber, Howard E. and Clark, W. Crawford",
volume="6",
number="3",
pages="97-106",
abstract="<p>[Abstract unavailable]</p>",
language="en",
issn="0031-5125",
doi="10.2466/pms.1956.6.3.97",
url="http://dx.doi.org/10.2466/pms.1956.6.3.97"
}