Борба за инвеституру — разлика између измена

* {{Cite book| ref=harv|author=Henry IV, Holy Roman Emperor|author-link=Henry IV, Holy Roman Emperor|year=1076|chapter=Henry IV.'s Answer to Gregory VII., Jan. 24, 1076|editor-last=Henderson|editor-first=Ernest F.|title=Select Historical Documents of the Middle Ages|url=https://archive.org/details/selecthistorical00hendiala|translator-last=Henderson|translator-first=Ernest F.