He was a member of the board of the Arbeiter Zeitung and secretary of the Vereingte Tischler New Yorks, a German joiners union based in the city, as well as a founding member of the International Labor Union established in Paterson, New Jersey in December 1878.
- "Speyer, Carl". www.leksikon.org. Retrieved 11 March 2017.
- Reick, Philipp (2016). "Labor is not a Commodity!": The Movement to Shorten the Workday in Late Nineteenth-Century Berlin and New York. Frankfurt/New York: Campus Verlag. p. 73.
- John R. Commons et al. History of Labour in the United States: Nationalisation (1860-1877) Volume 2 of History of Labour in the United States p. 301