Sahlfeld , W. “Méthode Intuitive: Interregional and International Circulation of a Pedagogical Idea (end of 19th Century)”. Rivista Di Storia dell’Educazione, Vol. 5, no. 2, Nov. 2018, pp. 59-72, https://rivistadistoriadelleducazione.it/index.php/rse/article/view/7621.