Columbia subject headings:
Harvard subject headings:
Grammar, Comparative and general--Negatives--Congresses.
Grammar, Comparative and general--Syntax--Congresses.
Language and languages--Variation--Congresses
Negation (Logic)--Congresses.
Princeton subject headings:
Grammar, Comparative and general--Negatives--Congresses.
Grammar, Comparative and general--Syntax--Congresses.
Language and languages--Variation--Congresses.
Negation (Logic)--Congresses.