Columbia subject headings:
German language--Grammar--Congresses.
German language--Spoken German--Congresses.
Harvard subject headings:
German language--Grammar, Comparative--Congresses.
German language--Grammar--Congresses.
German language--Spoken German--Congresses.
Princeton subject headings:
German language--Grammar, Comparative--Congresses.
German language--Grammar--Congresses.
German language--Spoken German--Congresses.