evidence: Brazil: Brazil and Bolivia have an ongoing dispute over the Isla Suárez/Ilha de Guajará-Mirim, on the Río Mamoré. The Roboré Accord (1958) put the island under Bolivian administration, but did not resolve the issue of sovereignty over the land. [...] In 1903, a piece of Bolivia's Acre Province, rich in rubber, was ceded to Brazil. And in 1938, after losing the Chaco War of 1932–1935 to Paraguay, Bolivia gave up its claim to nearly 100,000 sq mi of the Gran Chaco. Political instability ensued. [...] In 1971, Colonel Hugo Banzer Suarez led a third military coup and ruled as a dictator until 1978. A fourth coup deposed Banzer.