https://www.fpri.org/article/2017/03/nationality-ethnicity-e...
https://slate.com/news-and-politics/2017/03/many-ethnic-russ...
https://en.wikipedia.org/wiki/Russians_in_Estonia#Citizenshi...
https://ecpr.eu/filestore/paperproposal/3e77f4ab-9a20-4440-b...