Chronicon Fontanellense, Anno 855, 856 [1]Archived 3 December 2018 at the Wayback Machine; Annales de Saint Bertin, Anno 856, 858 [2]Archived 24 February 2011 at Wikiwix
Chronicon Fontanellense, Anno 855, 856 [1]Archived 3 December 2018 at the Wayback Machine; Annales de Saint Bertin, Anno 856, 858 [2]Archived 24 February 2011 at Wikiwix
Chronicon Fontanellense, Anno 855, 856 [1]Archived 3 December 2018 at the Wayback Machine; Annales de Saint Bertin, Anno 856, 858 [2]Archived 24 February 2011 at Wikiwix
Chronicon Fontanellense, Anno 855, 856 [1]Archived 3 December 2018 at the Wayback Machine; Annales de Saint Bertin, Anno 856, 858 [2]Archived 24 February 2011 at Wikiwix