@article{ref1,
title="Perception of topographical information (with reference to road signs)",
journal="Nature",
year="1962",
author="Walker, J.",
volume="195",
number="",
pages="522-522",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0028-0836",
doi="",
url="http://dx.doi.org/"
}