@article{ref1,
title="Non-medical use of painkillers in the USA",
journal="Lancet",
year="2011",
author="",
volume="378",
number="9804",
pages="1677-1677",
abstract="<p>[Abstract unavailable]</p> <p>Language: en</p>",
language="en",
issn="0140-6736",
doi="10.1016/S0140-6736(11)61723-6",
url="http://dx.doi.org/10.1016/S0140-6736(11)61723-6"
}