Columbia subject headings:
Communist International. Congress (1st : 1919 : Moscow, Russia)
International Socialist Congress.
International.
Socialism--Congresses.
Harvard subject headings:
Communist International. Congress (1st : 1919 : Moscow, Russia)
International Socialist Congress.
International Workingmen's Association.
Socialism--Congresses
Princeton subject headings:
Communist International (1st Congress : 1919 : Moscow, Russia)
International organization.
Socialism--Congresses.
Socialist International (1889-1922)