@article{ref1,
title="Geographical variations in senile osteoporosis. The association with physical activity",
journal="Journal of bone and joint surgery: British volume",
year="1970",
author="Chalmers, J. and Ho, K. C.",
volume="52",
number="4",
pages="667-675",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0301-620X",
doi="",
url="http://dx.doi.org/"
}