Columbia subject headings:
Crops and climate--Europe--History.
Crops and climate--Mexico--History.
Famines--Europe--History.
Famines--Mexico--History.
Harvard subject headings:
Crops and climate--Europe--History.
Crops and climate--Mexico--History.
Famines--Europe--History.
Famines--Mexico--History.
Princeton subject headings:
Crops and climate--Europe--History.
Crops and climate--Mexico--History.
Famines--Europe--History.
Famines--Mexico--History.