Jonathan D Huppert and Smith, Thomas E. 2001. “Longitudinal Analysis Of Subjective Quality Of Life In Schizophrenia: Anxiety As The Best Symptom Predictor”. The Journal Of Nervous And Mental Disease, 189, Pp. 669–675. https://journals.lww.com/jonmd/Abstract/2001/10000/Longitudinal_Analysis_of_Subjective_Quality_of.3.aspx.