Columbia subject headings:
Copper industry and trade--Zambia.
Mineral industries--Botswana.
Mineral industries--Developing countries.
Harvard subject headings:
Copper industry and trade--Zambia.
Developing countries--Mineral industries.
Mineral industries--Botswana.
Mineral industries--Developing countries
Princeton subject headings:
Copper industry and trade--Zambia.
Mineral industries--Botswana.
Mineral industries--Developing countries.