Columbia subject headings:
Indo-European languages--Grammar, Comparative--Congresses.
Indo-European languages--Grammatical categories--Congresses.
Harvard subject headings:
Indo-European languages--Grammar, Comparative--Congresses.
Indo-European languages--Grammatical categories--Congresses.
Princeton subject headings:
Indo-European languages--Grammar, Comparative--Congresses.
Indo-European languages--Grammatical categories--Congresses.