Columbia subject headings:
Populism--Baltic States--History--19th century.
Revolutionaries--Baltic States--History--19th century.
Socialism--Baltic States--History--19th century.
Harvard subject headings:
Populism--Baltic States--History--19th century.
Revolutionaries--Baltic States--History--19th century.
Socialism--Baltic States--19th century.
Socialism--Baltic States--History--19th century.
Princeton subject headings:
Populism--Baltic States--History--19th century.
Revolutionaries--Baltic States--History--19th century.
Socialism--Baltic States--History--19th century.