Found in articles
رویداد درگذشت. مُهر هاینریش چهارم Wikipedia contributors, "Henry IV, Holy Roman Emperor," Wikipedia, The Free Encyclopedia, (accessed August 18, 2011).
contributors, "Louis IV, Holy Roman Emperor," Wikipedia, The Free Encyclopedia, http://en.wikipedia.org/w/index.php?title=Louis_IV,_Holy_Roman_Emperor&oldid=448218106
Pohlsander, The Emperor Constantine, 68. Cameron, The Reign of Constantine, 68. Barnes, Constantine and Eusebius, 40–41. Potter, The Roman Empire at Bay
contributors, "Otto IV, Holy Roman Emperor," Wikipedia, The Free Encyclopedia, http://en.wikipedia.org/w/index.php?title=Otto_IV,_Holy_Roman_Emperor&oldid=445032887
فهرست پاپهای کلیسای کاتولیک روم
Herbermann, Charles (ed.). Catholic Encyclopedia. New York: Robert Appleton Company. Paschal Robinson (1913). "Pope Martin IV" . In Herbermann, Charles (ed.)