Columbia subject headings:
Harvard subject headings:
Agricultural surveys--Germany--Aachen (Regierungsbezirk)--History--19th century.
Agriculture--Germany--Aachen (Regierungsbezirk)--History--19th century.
Schwerz, Johann Nepomuk von, 1759-1844.
Princeton subject headings:
Aachen (Germany)--History.
Agriculture--Germany (West)--Aachen Region.