@article{ref1,
title="Differences in mortality after fracture of hip. Doubt remains over anticoagulant prophylaxis for deep venous thrombosis",
journal="British medical journal: BMJ",
year="1995",
author="Calder, J. and Ashby, E. C.",
volume="311",
number="7004",
pages="571; author reply 572-3",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0959-8138",
doi="",
url="http://dx.doi.org/"
}