Columbia subject headings:
Geodesy--North America--Congresses.
Nets (Geodesy)--Congresses.
Harvard subject headings:
Geodesy--North America--Congresses.
Nets (Geodesy)--Congresses.
Nets (Geodesy)--North America--Congresses.
Princeton subject headings:
Geodesy--North America--Congresses.
Nets (Geodesy)--North America--Congresses.