@article{ref1,
title="Estrogen and postmenopausal osteoporosis",
journal="Annals of internal medicine",
year="1993",
author="Gordan, G. S.",
volume="118",
number="2",
pages="155; author reply 156-155; author reply 156",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0003-4819",
doi="",
url="http://dx.doi.org/"
}