@article{ref1,
title="Aggressiveness: instinct or learned behavior",
journal="Revista de Medicina de la Universidad de Navarra",
year="2000",
author="Gonzalo, L. M.",
volume="44",
number="4",
pages="48-50",
abstract="<p>[Abstract unavailable]</p><p>Language: es</p>",
language="es",
issn="0556-6177",
doi="",
url="http://dx.doi.org/"
}