Summary of symptoms in ICD-11
https://icd.who.int/dev11/l-m/en#/http%3a%2f%2fid.who.int%2ficd%2fentity%2f36155616; https://icd.who.int/dev11/l-m/en#/http%3a%2f%2fid.who.int%2ficd%2fentity%2f109043312; https://icd.who.int/dev11/l-m/en#/http%3a%2f%2fid.who.int%2ficd%2fentity%2f253124068
There is a breadth of research available on the final pages of the guidelines published by the AWMF (Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V.). Starting on page 36, there are several expert sources listed: http://www.awmf.org/uploads/tx_szleitlinien/051-030l_S2k_Depersonalisations_Derealisationssyndrom_2014-09.pdf
Also, books by the author Matthias Michal contain a breadth of sources. Regular and targeted searches on the Internet are worth doing, as new research is constantly published.
Elena Bezzubova, a psychoanalyst, runs a blog with different posts on depersonalization disorder: https://www.psychologytoday.com/nz/blog/the-search-self/201610/depersonalization-philosophical-awareness