Columbia subject headings:
Commerce--Mathematical models.
Equilibrium (Economics)--Mathematical models.
Nonrenewable natural resources--Mathematical models.
Harvard subject headings:
Commerce--Mathematical models
Equilibrium (Economics)--Mathematical models.
International trade--Mathematical models
Nonrenewable natural resources--Mathematical models.
Princeton subject headings:
Commerce--Mathematical models.
Equilibrium (Economics)--Mathematical models.
Nonrenewable natural resources--Mathematical models.