@article{ref1,
title="Mental Differences Between Individuals",
journal="Occupational psychology",
year="1970",
author="Burt, C.",
volume="44",
number="1-4",
pages="141-147",
abstract="[Abstract unavailable]  <p>Language: en</p>",
language="en",
issn="0029-7976",
doi="",
url="http://dx.doi.org/"
}