@article{ref1,
title="The formal theory of behaviour",
journal="International journal of social psychiatry",
year="1977",
author="Levis, A. J.",
volume="23",
number="2",
pages="79-93",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0020-7640",
doi="",
url="http://dx.doi.org/"
}