Marshall McLuhan, W. Terrence Gordon, Elena Lamberti, Dominique Scheffel-Dunand (2011). “The Gutenberg Galaxy: The Making of Typographic Man”, p.330, University of Toronto Press
Oliver Goldsmith, Carl Theodor von KERSTEN (1857). “Goldsmith's Vicar of Wakefield employed as a means of reading made easy without any alteration of orthography ... By Charles Theodor von Kersten”, p.69