@article{ref1,
title="Choices of colored blocks in the play of preschool children",
journal="Perceptual and motor skills",
year="1969",
author="Gramza, A. F. and Witt, P. A.",
volume="29",
number="3",
pages="783-787",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0031-5125",
doi="",
url="http://dx.doi.org/"
}