Columbia subject headings:
Gardens--History--Congresses.
Gardens--Social aspects--History--Congresses.
Landscape architecture--History--Congresses.
Harvard subject headings:
Gardens--History--18th century--Congresses.
Gardens--History--19th century--Congresses.
Gardens--Social aspects--History--18th century--Congresses.
Gardens--Social aspects--History--19th century--Congresses.
Princeton subject headings:
Gardens--History--18th century--Congresses.
Gardens--History--19th century--Congresses.
Gardens--Social aspects--History--18th century--Congresses.
Gardens--Social aspects--History--19th century--Congresses.