Columbia subject headings:
Gardens--Symbolic aspects--Europe--History--Congresses.
Labyrinths--Europe--History--Congresses.
Landscape architecture--Europe--History--Congresses.
Maze gardens--Europe--History--Congresses.
Harvard subject headings:
Gardens--History
Gardens--History--Congresses.
Gardens--Symbolic aspects
Gardens--Symbolic aspects--Congresses.
Labyrinths--History--Congresses.
Labyrinths.
Maze gardens--History--Congresses.
Princeton subject headings:
Gardens--History.
Gardens--Symbolic aspects.
Labyrinths.