King, David A. (2007). Astrolabes and Angels, Epigrams and Enigmas - From Regiomontanus’ Acrostic for Cardinal Bessarion to Piero della Francesca’s Flagellation of Christ - An essay by DAK inspired by two remarkable discoveries by Berthold Holzschuh. Stuttgart. ISBN978-3-515-09061-2.. Material adicional en la página de King http://www.davidaking.org/.