Columbia subject headings:
Amazon River Valley.
Bolivia--Description and travel.
Brazil--Description and travel.
Peru--Description and travel.
United States--Discovery and exploration.
Harvard subject headings:
Amazon River Valley--Description and travel.
Amazon River Valley--Discovery and exploration--American.
Amazon River Valley.
America--Discovery and exploration.
Bolivia--Description and travel.
Brazil--Description and travel.
Peru--Description and travel
Princeton subject headings:
Amazon River Valley.
Bolivia--Description and travel.
Brazil--Description and travel--Description and travel.
Peru--Description and travel.
United States--Exploring expeditions.