Archiv-Nr. 31-121-1, handschriftlicher Entwurf 1933; Einstein Archives Online, Hebrew University of Jerusalem/California Institute of Technology/Princeton University Press, abgerufen am 28. November 2015.
Robert W. McChesney, Ben Scott: Upton Sinclair and the contradictions of capitalist journalism. In: Monthly Review 54.1 (Mai 2002), S. 1–14. „[m]ost newspapers refused to review the book, and those very few that did were almost always unsympathetic. Many newspapers, like the ''New York Times'', even refused to run paid advertisements for the book.“
Robert W. McChesney, Ben Scott: Upton Sinclair and the contradictions of capitalist journalism. In: Monthly Review 54.1 (Mai 2002), S. 1–14. „..those historians who bother to mention The Brass Check dismiss it as ephemeral, explaining that the problems it depicts have been solved.“
Steve Trott: Upton Sinclair & The Jungle. The centenary of an anti-capitalist classic. In: Socialist standard. Nr.1227. World socialism, November 2006 (englisch, worldsocialism.org).