Columbia subject headings:
Roads--Economic aspects--Peru--Inka.
Roads--Economic aspects--South America.
South America--Boundaries.
South America--Commerce.
South America--Economic integration.
Transportation--South America--International cooperation.
Harvard subject headings:
Roads--Economic aspects--Peru--Inka.
Roads--Economic aspects--South America.
South America--Boundaries.
South America--Commerce.
South America--Economic integration.
Transportation--South America--International cooperation.
Princeton subject headings:
Roads--Brazil.
Roads--Economic aspects--Brazil.
Roads--Economic aspects--Peru.
Roads--Peru.
Roads--Social aspects--Brazil.
Roads--Social aspects--Peru.