@article{ref1,
title="Central spatial structures and their development",
journal="Monographs of the society for research in child development",
year="1996",
author="Case, R. and Stephenson, K. M. and Bleiker, C. and Okamoto, Y.",
volume="61",
number="1-2",
pages="103-130",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0037-976X",
doi="",
url="http://dx.doi.org/"
}