@article{ref1,
title="Injuries caused by tripping over paving stones: an unappreciated problem",
journal="British medical journal: BMJ",
year="1990",
author="David, H. G. and Freedman, L. S.",
volume="300",
number="6727",
pages="784-785",
abstract="<p>[Abstract unavailable]</p> <p>Language: en</p>",
language="en",
issn="0959-8138",
doi="",
url="http://dx.doi.org/"
}