Columbia subject headings:
Harvard subject headings:
Crises (Philosophy)--Congresses.
Disasters--Social aspects--Congresses.
Social history--Congresses
Social problems in literature--Congresses.
Social problems--Congresses
Princeton subject headings:
Crises (Philosophy)--Congresses.
Disasters--Social aspects--Congresses.
Social history--Congresses.
Social problems in literature--Congresses.
Social problems--Congresses.