Columbia subject headings:
Harvard subject headings:
Agriculture--Italy--Arborea--History--20th century--Congresses.
Arborea (Italy)--Civilization--20th century--Congresses.
Arborea (Italy)--History--20th century--Congresses.
Princeton subject headings:
Agriculture--Italy--Arborea--History--20th century--Congresses.
Arborea (Italy)--History--20th century--Congresses.