American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders
(5th ed.). Washington, DC: Author.
Link for online version of DSM-5:
http://dsm.psychiatryonline.org/doi/book/10.1176/appi.books.9780890425596
Craighead, W.E., Miklowitz, D.J., & Craighead, L.W. (2017). Psychopathology: History, Diagnosis,
and Empirical Foundations. San Francisco, CA: John Wiley & Sons.

The psychopathology paper has some thoughts listed in it.