Columbia subject headings:
Gardens in literature--Congresses.
Gardens--Social aspects--Congresses.
Gardens--Symbolic aspects--Congresses.
Harvard subject headings:
Allotment gardens--Social aspects--Europe--Congresses.
Gardening--Social aspects--Europe--History--Congresses.
Gardens--Design--Europe--History--Congresses.
Gardens--Religious aspects--Congresses.
Gardens--Social aspects--Europe--History--Congresses.
Princeton subject headings:
Gardens in literature--Congresses.
Gardens--Social aspects--Congresses.
Gardens--Symbolic aspects--Congresses.