Columbia subject headings:
Harvard subject headings:
German language--Estonia--Congresses.
Multiculturalism--Estonia--Congresses.
Multilingualism--Estonia--Congresses.
Russian language--Estonia--Congresses.
Princeton subject headings:
Estonian language--Congresses.
German language--Estonia--Congresses.
Multiculturalism--Estonia--Congresses.
Multilingualism--Estonia--Congresses.
Russian language--Estonia--Congresses.