Columbia subject headings:
Nicholas I, Emperor of Russia, 1796-1855.
Russia--History--Nicholas I, 1825-1855.
Harvard subject headings:
Nicholas I, Emperor of Russia, 1796-1855.
Russia--History--Nicholas I, 1825-1855.
Princeton subject headings:
Nicholas I, Emperor of Russia, 1796-1855.
Russia--History--Nicholas I, 1825-1855.