@article{ref1,
title="Natural history of mental retardation: some aspects of epidemiology",
journal="American journal of mental deficiency",
year="1973",
author="Tarjan, G. and Wright, S. W. and Eyman, R. K. and Keeran, C. V.",
volume="77",
number="4",
pages="369-379",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0002-9351",
doi="",
url="http://dx.doi.org/"
}