Columbia subject headings:
Harvard subject headings:
Agriculture--Economic aspects--Belgium--Liège (Province)
Liège (Belgium : Province)--Economic conditions.
Liège (Belgium : Province)--Population--History.
Liège (Belgium : Province)--Social conditions.
Princeton subject headings:
Liège (Belgium)--Economic conditions.
Liège (Belgium)--History.
Liège (Belgium)--Social conditions.