Columbia subject headings:
Architecture, Modern--20th century.
Building, Iron and steel.
Framing (Building)
Tall buildings.
Harvard subject headings:
Architecture--Germany--20th century--Designs and plans.
Building, Iron and steel--Germany--Designs and plans.
Office buildings--Germany--Designs and plans.
Skyscrapers--Germany--Designs and plans.
Tall buildings--Germany--Designs and plans.
Princeton subject headings: