Columbia subject headings:
Civilization, Modern--20th century--Encyclopedias.
Philosophy--History--20th century--Encyclopedias.
Social sciences--History--20th century--Encyclopedias.
Harvard subject headings:
Civilization, Modern--20th century--Encyclopedias.
Philosophy, Modern--20th century--Encyclopedias.
Social sciences--History--20th century--Encyclopedias.
Princeton subject headings:
Civilization, Modern--20th century--Encyclopedias.
Philosophy--History--20th century--Encyclopedias.
Social sciences--History--20th century--Encyclopedias.