@article{ref1,
title="Distance discrimination; the relationship of visual acuity to distance discrimination",
journal="Journal of aviation medicine",
year="1948",
author="Hirsch, M. J. and Weymouth, F. W.",
volume="19",
number="1",
pages="56-58",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0095-991X",
doi="",
url="http://dx.doi.org/"
}