@article{ref1,
title="The concept of nervous system levels",
journal="Neuroscience and behavioral physiology",
year="1980",
author="Kukuev, L. A.",
volume="10",
number="1",
pages="1-5",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0097-0549",
doi="",
url="http://dx.doi.org/"
}