Columbia subject headings:
Geology, Stratigraphic--Paleozoic--Congresses.
Orogenic belts--Europe--Congresses.
Orogenic belts--North America--Congresses.
Harvard subject headings:
Geology, Stratigraphic--Paleozoic--Congresses
Orogeny--Europe--Congresses.
Orogeny--North America--Congresses.
Princeton subject headings:
Geology, Stratigraphic--Paleozoic--Congresses.
Orogeny--Europe--Congresses.
Orogeny--North America--Congresses.