@Book{BVMC:625440, author = {Iglesia Católica. Papa (0432-0440: Sixto III)}, title = {Sancti Sixti Tertij Pontificis Maximi Liber de diuitijs}, url = {https://www.cervantesvirtual.com/obra/sancti-sixti-tertij-pontificis-maximi-liber-de-diuitijs} }