Columbia subject headings:
Agriculture--Economic aspects--Spain--Aragon--History.
Aragon (Spain)--Population--History.
Feudalism--Spain--Aragon--History.
Land tenure--Spain--Aragon--History.
Social structure--Spain--Aragon--History.
Harvard subject headings:
Agriculture--Economic aspects--Spain--Aragon--History.
Aragon (Spain)--Population--History.
Feudalism--Spain--Aragon--History.
Land tenure--Spain--Aragon--History.
Social structure--Spain--Aragon--History.
Princeton subject headings:
Aragon (Spain)--Economic conditions.
Aragon (Spain)--History--Sancho Ramírez, 1063-1094.
Aragon (Spain)--Social conditions.