Lithium efficacy in bipolar depression with flexible dosing: A six-week, open-label, proof-of-concept study - Machado-Vieira, Rodrigo; Zanetti, Marcus V.; De Sousa, Rafael T.; Soeiro‑De‑Souza, Marcio G.; Moreno, Ricardo A.; Busatto, Geraldo F.; Gattaz, Wagner F. (Experimental and Therapeutic Medicine, 2014)