Columbia subject headings:
Greenbelts--California--Congresses.
Parks--California--Congresses.
Regional planning--California--Congresses.
Harvard subject headings:
Greenbelts--California--Congresses.
Parks--California--Congresses.
Regional planning--California--Congresses.
Princeton subject headings:
Greenbelts--California--Congresses.
Parks--California--Congresses.
Regional planning--California--Congresses.