Salvador Miranda. "Cardinals of the 13th Century". The Cardinals of the Holy Roman Church. Diarsipkan dari versi asli tanggal 2019-04-15. Diakses tanggal 10 February 2019.
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Salvador Miranda. "Cardinals of the 13th Century". The Cardinals of the Holy Roman Church. Diarsipkan dari versi asli tanggal 2019-04-15. Diakses tanggal 10 February 2019.