@article{ref1,
title="IPV and Late Preterm Birth",
journal="AWHONN lifelines",
year="2009",
author="Roller, Cynthia",
volume="13",
number="1",
pages="11-12",
abstract="<p>[Abstract unavailable]</p>",
language="",
issn="1091-5923",
doi="10.1111/j.1751-486X.2009.01375.x",
url="http://dx.doi.org/10.1111/j.1751-486X.2009.01375.x"
}