@article{article66000635,
title   = {Melatonin levels in drug-free patients with major depression from the southern hemisphere},
author = {Carvalho, Livia A. and Gorenstein, Clarice and Moreno, Ricardo A. and Markus, Regina P},
year = {2006},
doi = {10.1016/j.psyneuen.2006.02.010},
journal   = {Psychoneuroendocrinology}
}