Antipope Sylvester IV (English Wikipedia)

Analysis of information sources in references of the Wikipedia article "Antipope Sylvester IV" in English language version.

refsWebsite

Global rank English rank

182^nd place

981^st place

6^th place

6^th place

archive.org

Roger Collins (2009), Keepers of the Keys of Heaven: A History of the Papacy, Basic Books, pp. 221–223, ISBN 9780465011957

treccani.it

Andrea Piazza (2018). "Silvestro IV, antipapa". Dizionario Biografico degli Italiani, Volume 92: Semino–Sisto IV (in Italian). Rome: Istituto dell'Enciclopedia Italiana. ISBN 978-8-81200032-6.