Columbia subject headings:
Harvard subject headings:
Commerce--History--Medieval, 500-1500--Sources
Spain--Commerce--Handbooks, manuals, etc.--History--Sources.
Spain--Commerce--History--Sources.
Princeton subject headings:
Commerce--History--Medieval, 500-1500--Sources.
Spain--Commerce--Handbooks, manuals, etc.--History--Sources.
Spain--Commerce--History--Sources.