May-Collado, L. J., and D. Wartzok. “Sounds Produced by the Tucuxi (<i>Sotalia fluviatilis</I>) from the Napo and Aguarico Rivers of Ecuador”. Latin American Journal of Aquatic Mammals, vol. 8, no. 1-2, Dec. 2010, pp. 131-6, doi:10.5597/lajam00162.