Columbia subject headings:
Harvard subject headings:
Diplomacy--History
Diplomatic gifts--History--Congresses.
Diplomatic gifts--History.
Europe--Foreign relations--History--Congresses.
Europe--Politics and government--Congresses.
International relations--History
Social exchange--History.
Princeton subject headings:
Diplomatic gifts--History--Congresses.
Europe--Foreign relations--History--Congresses.
Europe--Politics and government--Congresses.