Columbia subject headings:
Philosophy--Bibliography.
Philosophy--Encyclopedias.
Harvard subject headings:
Enlightenment--History.
Existentialism--History.
Neo-Scholasticism--History.
Phenomenology--History.
Philosophy, Modern--History.
Philosophy, Renaissance--History.
Positivism--History.
Princeton subject headings:
Encyclopedias.
Philosophy--Bibliography.
Philosophy--Encyclopedias.