Columbia subject headings:
Harvard subject headings:
Bridges--Argentina--Congresses.
Bridges--Uruguay--Congresses.
City planning--Argentina--Congresses.
City planning--Uruguay--Congresses.
Public works--Argentina--Congresses.
Public works--Uruguay--Congresses.
Working class--Argentina--Congresses.
Working class--Uruguay--Congresses.
Princeton subject headings:
Argentina--Relations--Uruguay--Congresses.
Bridges--Argentina--Congresses.
Bridges--Uruguay--Congresses.
Uruguay--Relations--Argentina--Congresses.