The Chaucer Review: An Indexed Bibliography (Vols. 1-30)

Ferris, Sumner. "John Stow and the Tomb of Blanche the Duchess." 18 (1983): 92-93.
John Stow's Survay of London records the date on Blanche of Lancaster's tomb as 1368, thus corroborating the likely date for the Book of the Duchess as 1368.