Columbia subject headings:
Astronomy--History--Congresses.
Copernicus, Nicolaus, 1473-1543--Congresses.
Harvard subject headings:
Astronomy--History--Congresses.
Copernicus, Nicolaus, 1473-1543.
Princeton subject headings:
Astronomy--History--Congresses.
Copernicus, Nicolaus, 1473-1543--Congresses.