Editors. "Maximilian I summons the German princes to join him on a crusade". The Literary Encyclopedia. First published 01 November 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=14054, accessed 17 April 2014.]
Maximilian I calls on the princes of Germany to join him on a crusade, to set off on 1st June.