Chronicle of Council of Constance, p. 186r
<a href="https://en.wikipedia.org/wiki/Ulrich_von_Richental" class="extiw" title="w:Ulrich von Richental">Ulrich von Richental</a>
<a rel="nofollow" class="external text" href="https://digi.ub.uni-heidelberg.de/diglit/ir00196000/0370/image,info">Concilium zu Constencz (Chronik des Konstanzer Konzils)</a>