@article{ref1,
title="Modality, difficulty, and "coupling" in vigilance behavior",
journal="American journal of psychology",
year="1971",
author="Loeb, M. and Binford, J. R.",
volume="84",
number="4",
pages="529-541",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0002-9556",
doi="",
url="http://dx.doi.org/"
}