@article{ref1,
title="Participation in sports during pregnancy",
journal="Nederlands Tijdschrift voor Geneeskunde",
year="1989",
author="Rijn, J. and Grijpink, P. and Holm, J. P. and van Erp, E. J.",
volume="133",
number="4",
pages="179-179",
abstract="<p>[Abstract unavailable]</p><p>Language: nl</p>",
language="nl",
issn="0028-2162",
doi="",
url="http://dx.doi.org/"
}