Columbia subject headings:
Structural engineering--Congresses.
Tall buildings--Congresses.
Tall buildings--Design and construction--Congresses.
Harvard subject headings:
Skyscrapers--Congresses.
Structural engineering--Congresses
Tall buildings--Congresses.
Princeton subject headings:
Structural engineering--Congresses.
Tall buildings--Congresses.
Tall buildings--Design and construction--Congresses.