Columbia subject headings:
Social engineering--Europe--History--20th century--Congresses.
Social engineering--United States--History--20th century--Congresses.
Harvard subject headings:
Social engineering--Europe--History--20th century--Congresses.
Social engineering--United States--History--20th century--Congresses.
Princeton subject headings:
Social engineering--Europe--History--20th century--Congresses.
Social engineering--United States--History--20th century--Congresses.