Борба за инвеституру — разлика између измена

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* {{Cite book| ref=harv|last=Tellenbach|first=Gerd|author-link=Gerd Tellenbach|year=1993|title=The Western Church from the Tenth to the Early Twelfth Century|publisher=Cambridge University Press}}

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* {{Cite book| ref=harv|year=2007|chapter=Selected Sources: Empire and Papacy|url=https://sourcebooks.fordham.edu/halsall/sbook1l.asp|editor-last=Halsall|editor-first=Paul|title=Internet Medieval Sourcebook|location=New York|publisher=Fordham University|accessdate=13. 10. 2017.}}