Columbia subject headings:
Helvétius, 1715-1771.
Philosophers--France--Correspondence.
Harvard subject headings:
Helvétius, 1715-1771
Helvétius, 1715-1771--Correspondence.
Philosophers--France--Correspondence
Princeton subject headings:
Helvétius, 1715-1771.
Philosophers--France--Correspondence.