↑Enock, Charles Reginald (1914) Ecuador: its ancient and modern history, topography and natural resources, industries and social development Charles Scribner's sons, New York, pages 177–178, OCLC2453173
↑Ziesler, R. and G.D. Ardizzone, G.D. (1979) "Amazon System"Las Aguas Continentales de America Latina / The Inland Waters of Latin America (COPESCAL Technical Paper No. 1) Fisheries and Aquaculture Department, Food and Agriculture Organization of the United Nations (FAO), Rome, ISBN92-5-000780-9, in English and Spanish