Columbia subject headings:
Agriculture--Economic aspects--Spain--Aragon.
Agriculture--Social aspects--Spain--Aragon.
Canals--Spain.
Imperial Canal (Spain)
Water in agriculture--Spain--Aragon.
Harvard subject headings:
Agriculture--Economic aspects--Spain--Aragon--History--18th century.
Aragon (Spain)--Economic conditions.
Imperial Canal (Spain)--History--18th century.
Irrigation--Economic aspects--Spain--Aragon--History--18th century.
Princeton subject headings:
Agriculture--Economic aspects--Spain--Aragón.
Agriculture--Social aspects--Spain--Aragón.
Canals--Spain.
Imperial Canal (Spain)
Water in agriculture--Spain--Aragón.