A. Cordero-Villafáfila, J. A. Ramos-Brieva, R. Gutiérrez Labrador, and M. L. Zamarro Arranz, “A brief and rapid procedure to measure the intensity of depressive symptoms in Primary Care”, Actas Esp Psiquiatr, vol. 39, no. 1, pp. 45–48, Jan. 2011.