@article{ref1,
title="The effect of massed versus spaced practice on auditory threshold",
journal="Acta psychologica",
year="1967",
author="Ramsay, R. W. and Utrecht, L. C. and Alkema, D.",
volume="26",
number="3",
pages="227-232",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0001-6918",
doi="",
url="http://dx.doi.org/"
}