Columbia subject headings:
Harvard subject headings:
Cant--Balkan Peninsula--Congresses.
Cant--Germany--Congresses.
Languages, Secret--Balkan Peninsula--Congresses.
Languages, Secret--Germany--Congresses.
Sublanguage--Balkan Peninsula--Congresses.
Sublanguage--Germany--Congresses.
Princeton subject headings:
Cant--Balkan Peninsula--Congresses.
Cant--Germany--Congresses.
Languages, Secret--Balkan Peninsula--Congresses.
Languages, Secret--Germany--Congresses.
Sublanguage--Balkan Peninsula--Congresses.
Sublanguage--Germany--Congresses.