References for "New insights into treatment-resistant depression"
Gaynes BN, et al. "The STAR*D Study: Treating Depression in the Real World," Cleveland Clinic Journal of Medicine (Jan. 2008): Vol. 75, No. 1, pp. 57–66.
Perlis RH, et al. "Association Between Bipolar Spectrum Features and Treatment Outcomes in Outpatients with Major Depressive Disorder," Archives of General Psychiatry (Dec. 6, 2010): Electronic publication ahead of print.