1. Dementia Praecox or the Group of Schizophrenia;Bleuler,1911
2. The Classification of Endogenous Psychoses;Leonhard,1957
3. Hierarchical diagnosis in chronic schizophrenia;Bermanzohn;Schizophr Bull,2000
4. Depression in schizophrenia;Becker;Hosp Commun Psychiatry,1988
5. Diagnosis of secondary depression in schizophrenia;Siris;Schizophr Bull,1991