Columbia subject headings:
Harvard subject headings:
Agriculture--Economic aspects--Portugal--Valença--History.
Land tenure--Portugal--Valença--History.
Mosteiro de Ganfei--History.
Valença (Portugal)--Economic conditions.
Princeton subject headings:
Agriculture--Economic aspects--Portugal--Valença.
Land tenure--Portugal--Valença--History.
Mosteiro de Ganfei (Valença, Portugal)--History.
Valença (Portugal)--Economic conditions.