Columbia subject headings:
Imaginary languages in literature--Congresses.
Imaginary languages--Congresses.
Languages, Mixed--Congresses.
Harvard subject headings:
Imaginary languages in literature--Congresses.
Imaginary languages--Congresses.
Languages, Mixed--Congresses.
Princeton subject headings:
Cryptography--Congresses.
Imaginary languages in literature--Congresses.
Imaginary languages--Congresses.
Languages, Mixed--Congresses.