Columbia subject headings:
Harvard subject headings:
Finland--History, Military--20th century.
Finland--Military relations--Soviet Union.
Fortification--Finland--History--20th century.
Karelian Isthmus (Russia)--Defenses.
Russo-Finnish War, 1939-1940
Soviet Union--Military relations--Finland.
World War, 1939-1945.
Princeton subject headings:
Finland--History, Military--20th century.
Finland--Military relations--Soviet Union.
Fortification--Finland--History--20th century.
Karelian Isthmus (Russia)--Defenses.
Russo-Finnish War, 1939-1940.
Soviet Union--Military relations--Finland.