Columbia subject headings:
Harvard subject headings:
Berdi︠a︡ev, Nikolaĭ, 1874-1948
Berdi︠a︡ev, Nikolaĭ, 1874-1948--Knowledge--Communism.
Bulgakov, Sergiĭ, 1871-1944--Knowledge--Communism.
Bulgakov, Sergiĭ, 1871-1944.
Communism
Philosophy, Russian--19th century.
Philosophy, Russian--20th century.
Socialism--Russia.
Tugan-Baranovskiĭ, M. I. (Mikhail Ivanovich), 1865-1919--Knowledge--Communism.
Tugan-Baranovskiĭ, M. I. (Mikhail Ivanovich), 1865-1919.
Princeton subject headings:
Berdi︠a︡ev, Nikolaĭ, 1874-1948--Knowledge--Communism.
Bulgakov, Sergiĭ, 1871-1944--Knowledge--Communism.
Communism.
Philosophy, Russian--19th century.
Philosophy, Russian--20th century.
Tugan-Baranovskiĭ, M. I. (Mikhail Ivanovich), 1865-1919--Knowledge--Communism.