en Ansel, Bernard D.: European Adventurer in Tierra del Fuego: Julio Popper, Hispanic American Historical Review, pp. 89-110, Vol. 50, No. 1, publ. Duke University Press, Feb. 1970 (Stable URL: http://www.jstor.org/stable/2511634).
en McCarthy, David: Julius Popper and the Coins of the Argentine Gold Rush, 27 octombrie 2009, http://www.pcgs.com/articles/detail/5915 (accesionat: 20 dec. 2011)