Lefèvre, Wolfgang Department Structural Changes in Systems of Knowledge, Max Planck Institute for the History of Science, Max Planck Society;
Lefèvre, W. (2010). Review of: Kranz, H. and W. Oberschelp: Mechanisches Memorieren und Chiffrieren um 1430: Johannes Fontanas 'Tractatus de instrumentis artis memorie'. Stuttgart: Steiner 2007. Historia Mathematica, 37(4), 710-712.