Columbia subject headings:
Chaadaev, P. I︠A︡. (Petr I︠A︡kovlevich), 1794-1856--Criticism and interpretation.
Harvard subject headings:
Chaadaev, P. I︠A︡. (Petr I︠A︡kovlevich), 1794-1856--Criticism and interpretation.
Princeton subject headings:
Chaadaev, P. I︠A︡. (Petr I︠A︡kovlevich), 1794-1856--Criticism and interpretation.