@article{ref1,
title="World at work: bricklayers and bricklayers' assistants",
journal="Occupational and environmental medicine",
year="2004",
author="van der Molen, H. F. and Veenstra, S. J. and Sluiter, J. K. and Frings-Dresen, Monique H. W.",
volume="61",
number="1",
pages="89-93",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="1351-0711",
doi="",
url="http://dx.doi.org/"
}