@article{ref1,
title="A Study of the Comparative Retardation of Negro and White Pupils in a Philadelphia Public School",
journal="Psychol Clin",
year="1915",
author="Perring, Louise F.",
volume="9",
number="3",
pages="87-93",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="",
doi="",
url="http://dx.doi.org/"
}