Illustration from the printed work <i>Unio pro co[n]servatio[n]e rei publice</i> (Antwerpen: Jan de Gheet 1515), showing Emperor Maximilian I singing the motet <i>Summe laudis o Maria</i> by Benedictus de Opitiis to the Virgin. Fol. Dv.
Printed work by Jan de Gheet, illustration by unknown artist
Lodes, Birgit (21 September 2016). "Musikalische Huldigungsgeschenke für Maximilian I." Musikleben des Spätmittelalters in der Region Österreich (in German). Retrieved 4 March 2022. Link:<a rel="nofollow" class="external free" href="https://musical-life.net/essays/musikalische-huldigungsgeschenke-fur-maximilian-i">https://musical-life.net/essays/musikalische-huldigungsgeschenke-fur-maximilian-i</a>