Analysis of information sources in references of the Wikipedia article "Roman Catholic Diocese of Gubbio" in English language version.
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: CS1 maint: location missing publisher (link) Ritzler-Sefrin, VII, pp. 124, 189; VIII, p. 46. Martin Bräuer (27 February 2014). Handbuch der Kardinäle: 1846-2012 (in German). Berlin: De Gruyter. p. 45. ISBN 978-3-11-026947-5.