@article{ref1,
title="The effect of a central task on luminance thresholds for peripherally presented stimuli",
journal="Human factors",
year="1969",
author="Appelle, S. and Leibowitz, H. W.",
volume="11",
number="4",
pages="387-392",
abstract="Abstract unavailable.",
language="",
issn="0018-7208",
doi="",
url="http://dx.doi.org/"
}