@article{ref1,
title="The effect of perspective geometry on judged direction in spatial information instruments",
journal="Human factors",
year="1986",
author="McGreevy, M. W. and Ellis, S. R.",
volume="28",
number="4",
pages="439-456",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0018-7208",
doi="",
url="http://dx.doi.org/"
}