1. Akiskal HS, Mallya G (1987) Criteria for the “soft” bipolar spectrum: treatment implications. Psychopharmacol Bull 23(1):68–73
2. American Psychiatric Association (1980) Diagnostic and statistical manual of mental disorders, 3rd edn. American Psychiatric Association, Washington, DC
3. American Psychiatric Association (1993) Diagnostic and statistical manual of mental disorders, 4th edn. American Psychiatric Association, Arlington, VA
4. American Psychiatric Association (2013) Diagnostic and statistical manual of mental disorders, 5th edn. American Psychiatric Association, Arlington, VA
5. Angst J (1966) Zur Ätiologie und Nosologie endogenor depressiver Psychosen. Eine genetische, soziologische und klinische Studie. Springer, Berlin