Dietzgen, Joseph - en: Excursions of a Socialist into the Domain of Epistemology (English translation in Dietzgen, E. & J. (eds.) - Some of the Philosophical Essays by Joseph Dietzgen. Charles H. Kerr, Chicago 1906, p. 263 – 362. online beschikbaar op Marxists Internet Archive (MIA). Gearchiveerd op 25 mei 2023.
Dietzgen, Joseph - en: Excursions of a Socialist into the Domain of Epistemology (English translation in Dietzgen, E. & J. (eds.) - Some of the Philosophical Essays by Joseph Dietzgen. Charles H. Kerr, Chicago 1906, p. 263 – 362. online beschikbaar op Marxists Internet Archive (MIA). Gearchiveerd op 25 mei 2023.