@article{ref1,
title="Epidemiological considerations of psychotic depression",
journal="Archives of general psychiatry",
year="1972",
author="Pederson, A. M. and Barry, D. J. and Babigian, H. M.",
volume="27",
number="2",
pages="193-197",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0003-990X",
doi="",
url="http://dx.doi.org/"
}