Columbia subject headings:
Fortification--Silesia, Upper (Poland and Czech Republic)
Mounds--Silesia, Upper (Poland and Czech Republic)
Harvard subject headings:
Fortification--Silesia, Upper (Poland and Czech Republic)
Fortification--Silesia, Upper (Poland and Czech Republic)--History.
Mounds--Silesia, Upper (Poland and Czech Republic)
Silesia, Upper (Poland and Czech Republic)--History, Military.
Princeton subject headings: