@article{ref1,
title="Hygienic effects of frequently playrooms on 1st grade pupils in elementary schools",
journal="Roczniki Panstwowego Zakladu Higieny",
year="1976",
author="Polus-Szeniawska, E.",
volume="27",
number="4",
pages="465-471",
abstract="<p>[Abstract unavailable]</p><p>Language: pl</p>",
language="pl",
issn="0035-7715",
doi="",
url="http://dx.doi.org/"
}