@article{ref1,
title="Cannabis and the increased incidence and persistence of psychosis",
journal="BMJ",
year="2011",
author="Hall, Wayne and Degenhardt, Louisa",
volume="342",
number="",
pages="d719-d719",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0959-535X",
doi="",
url="http://dx.doi.org/"
}