The role of socio-economic status in depression: results from the COURAGE (aging survey in Europe) - Aislinne Freeman; Stefanos Tyrovolas; Ai Koyanagi; Somnath Chatterji; Matilde Leonardi; Jose Luis Ayuso-Mateos; Beata Tobiasz-Adamczyk; Seppo Koskinen; Christine Rummel-Kluge; Josep Maria Haro (BMC Public Health, 2016)