Columbia subject headings:
Conférence socialiste internationale de Stockholm (1917)--History--Sources.
International Socialist Congress--History--Sources.
International Socialist Congress. (1912 : Basel, Switzerland)--History--Sources.
Socialism--Congresses--History--Sources.
Harvard subject headings:
Socialism--Europe--Congresses
Socialist International (1889-1922)
Princeton subject headings:
Socialism--Europe--Congresses.
Socialist International (1889-1922)