Columbia subject headings:
Reference (Linguistics)--Congresses.
Semiotics--Congresses.
Signs and symbols--Congresses.
Harvard subject headings:
Reference (Linguistics)--Congresses.
Semiotics--Congresses.
Signs and symbols--Congresses
Princeton subject headings:
Reference (Linguistics)--Congresses.
Semiotics--Congresses.
Signs and symbols--Congresses.