Columbia subject headings:
Cossacks--History.
Russia--History--Michael, 1613-1645.
Russia--History--Time of Troubles, 1598-1613.
Harvard subject headings:
Cossacks--History--17th century.
Russia--History--Time of Troubles, 1598-1613.
Princeton subject headings:
Russia--History--Michael, 1613-1645.
Russia--History--Time of Troubles, 1598-1613.