Columbia subject headings:
Agriculture--England--West Riding of Yorkshire--Early works to 1800.
Harvard subject headings:
Agriculture--England--Berkshire.
Agriculture--England--Cumbria.
Agriculture--England--Humberside.
Agriculture--England--Lancashire.
Agriculture--England--North Yorkshire.
Berkshire (England)--Economic conditions.
Cumbria (England)--Economic conditions.
Humberside (England)--Economic conditions.
Lancashire (England)--Economic conditions.
North Yorkshire (England)--Economic conditions.
Princeton subject headings:
Agriculture--England--Yorkshire.