Zhyvago, K. S. “Predisposition to Depressive Symptoms in Patients With Paranoid Schizophrenia: Constitutional-Biological, Socio-Demographic Factors and the Debut of the Disease”. Zaporozhye Medical Journal, vol. 18, no. 6, Dec. 2016, doi:10.14739/2310-1210.2016.6.85530.