William Westcott Kibler, ed. Medieval France: An Encyclopedia (New York: Garland Publishing, 1995),[full citation needed] sub "Narbonne", following abbé Sigal, "Les origines de la cathédrale de Narbonne" Bulletin de la Commission Archéologique de Narbonne, Année 1921 (Toulouse 1921).[page needed]; Sigal's date for the cathedral tower: p. 124.
books.google.com
Joseph Hyacinthe Albanès & Ulysse Chevalier, Gallia christiana novissima: histoire des archevêchés, évêchés & abbayes de France: Arles., (in Latin and French) Volume 3 (Valence: Valentinoise, 1901), p. 36. Pope Leo I, congratulatory letter no. XL, 22 August 449.
ccel.org
Joseph Hyacinthe Albanès & Ulysse Chevalier, Gallia christiana novissima: histoire des archevêchés, évêchés & abbayes de France: Arles., (in Latin and French) Volume 3 (Valence: Valentinoise, 1901), p. 36. Pope Leo I, congratulatory letter no. XL, 22 August 449.