Helen of Laval, baroness of Derval, Ownership Confirmed (post-1450-1500?) by Other.
Dupic, Jeanne. "Un Bibliophile breton, Jean de Derval." In Les Trésors de bibliothèques de France: Manuscrits, incunables, livres rares, dessins, estampes, objets d'art, curiosités bibliographiques, ed. R. Cantinelli and Amédée Boinet (Paris: G Van Oest, 1935), 157-62.