Columbia subject headings:
Harvard subject headings:
Linen industry--Northern Ireland--Maghera Region (Magherafelt)--History.
Linen industry--Northern Ireland--Upperlands--History.
Maghera (Londonderry, Northern Ireland)--History.
William Clark & Sons--History.
Princeton subject headings:
Linen industry--Northern Ireland--Upperlands--History.
Upperlands (Northern Ireland)--History.