Graßhoff, Gerd Max Planck Fellow Computational History of Science, Max Planck Institute for the History of Science, Max Planck Society;
http://repository.edition-topoi.org/collection/MAPD (beliebiger Volltext)
Graßhoff, G., Liess, H.-C., Eastwood, B. S., & Schneider, D. (2016). Medieval diagrams (Database). doi:10.17171/1-2.