Columbia subject headings:
Harvard subject headings:
Forging--History--Congresses.
Metal-work--History--Congresses.
Metallurgy--History--Congresses.
Technology--History--Congresses
Princeton subject headings:
Forging--History--Congresses.
Metal-work--History--Congresses.
Metallurgy--History--Congresses.
Technology--History--Congresses.