Columbia subject headings:
Harvard subject headings:
Fortification--Italy--Alessandria (Province)--History--20th century.
Fortification--Italy--Ligurian Alps--History--20th century.
Mountain warfare.
World War, 1939-1945--Italy--Alessandria (Province)
World War, 1939-1945--Italy--Ligurian Alps.
Princeton subject headings:
Fortification--Italy--Liguria.