Adalard, Count of Vermandois, son of Gisla, granddaughter of Charlemagne, count of Vermandois (833–864) and then abbot of St Quentin de Monte (844–864).
Teutricius (864–886) and then abbot of St Quentin de Monte (879–886) or Theodoric, Count of Vermandois (c. 876), a descendant of Childebrand, brother of Charles Martel.
Anselme, Histoire Genealogique de la Maison royale de France, 1726.
M. Fouquier-Cholet, Histoire des Comtes héréditaires du Vermandois, Saint-Quentin, 1832.
Ioh. Mabillon, Annales ord. Sancti Benedicti. Ticinense. Lucae, 1739.
Louis Moreri, Le Gran Dictionnaire Historique, Paris, 1743–1749.
Gabriele, Matthew (2018). "The Provenance of the Descriptio Qauliter Karolus Magnus: Remembering the Carolingians in the entourage of King Philip I (1060–1108) before the First Crusade". Viator. 39 (2). University of California Press: 93-117.