Columbia subject headings:
Industries--Belgium--Verviers--History--18th century.
Industries--Belgium--Verviers--History--19th century.
Verviers (Belgium)--Population--History--18th century.
Verviers (Belgium)--Population--History--19th century.
Harvard subject headings:
Industries--Belgium--Verviers--History--18th century.
Industries--Belgium--Verviers--History--19th century.
Verviers (Belgium)--Population--History--18th century.
Verviers (Belgium)--Population--History--19th century.
Princeton subject headings:
Industries--Belgium--Verviers--History--19th century.
Verviers (Belgium)--Population--History--19th century.
Verviers (Belgium)--Statistics, Vital.