Columbia subject headings:
Helvétius, 1715-1771.
Holbach, Paul Henri Thiry, baron d', 1723-1789.
Rousseau, Jean-Jacques, 1712-1778.
Harvard subject headings:
Helvétius, 1715-1771.
Holbach, Paul Henri Thiry, baron d', 1723-1789.
Rousseau, Jean-Jacques, 1712-1778
Princeton subject headings: