Columbia subject headings:
Europe, Eastern--History.
Ludat, Herbert, 1910-1993.
Slavic countries--History.
Harvard subject headings:
Europe, Eastern--History.
Ludat, Herbert, 1910---Bibliography.
Ludat, Herbert, 1910-1993.
Slavic countries--History.
Princeton subject headings:
Europe, Eastern--History.
Ludat, Herbert, 1910-1993.
Slavic countries--History.