Marjolaine Lémeillat, "Two holders for one viscount? The quarrels between Isabelle of Spain, Duchess of Brittany, Viscountess of Limoges, with Guy de Bretagne, Viscount of Limoges", Annales de Bretagne et des pays de l'Ouest [fr], vol. 126, number 2 "The Viscount of Limoges under the Dukes of Brittany, XIIIth - XVth century", 2019, p. 85-105 (DOI 10.4000/abpo.4507)