Columbia subject headings:
Historians--Soviet Union--Congresses.
Russia--History--1801-1917--Congresses.
Zaĭonchkovskiĭ, P. A. (Petr Andreevich)--Congresses.
Harvard subject headings:
Historians--Soviet Union--Biography
Russia--History--1801-1917.
Soviet Union--History.
Zaĭonchkovskiĭ, P. A. (Petr Andreevich)
Princeton subject headings: