Columbia subject headings:
Gardens in literature--Congresses.
Gardens--Italy--History--Congresses.
Historic gardens--Italy--Congresses.
Harvard subject headings:
Gardens in literature--Congresses.
Gardens, Italian--Congresses.
Gardens--Italy--History--Congresses.
Historic gardens--Italy--Congresses.
Princeton subject headings:
Gardens in literature--Congresses.
Gardens, Italian--Congresses.
Gardens--Italy--History--Congresses.
Historic gardens--Italy--Congresses.