@article{ref1,
title="Play in early infancy",
journal="Medicina (Madr)",
year="1956",
author="Sainz de los terreros y ranero, L.",
volume="24",
number="2",
pages="63-68",
abstract="<p>[Abstract unavailable]</p><p>Language: es</p>",
language="es",
issn="0025-7710",
doi="",
url="http://dx.doi.org/"
}