@article{ref1,
title="Visual threshold: human scotopic luminosity functions determined with optokinetic nystagmus",
journal="Vision research",
year="1973",
author="Metz, J. W. and Balliet, R. F.",
volume="13",
number="5",
pages="1001-1004",
abstract="<p>[Abstract unavailable]</p> <p>Language: en</p>",
language="en",
issn="0042-6989",
doi="",
url="http://dx.doi.org/"
}