Viollet-le-Duc, E. Dictionnaire Raisonné de l’Architecture française du XIᵉ au XVIᵉ Siècle. 10 vols. Paris, 1854, etc.
—— Essai sur l’architecture militaire au moyen âge. Paris, 1854 (translated by M. Macdermott, Oxford and London, 1860).
—— Histoire d’une forteresse. Paris, n.d.
Ward, W. H. French Châteaux and Gardens in the XVIth Century (drawings reproduced from Androuet-du-Cerceau). London, 1909.
Westropp, T. J. Irish motes and alleged Norman castles (Proc. Royal Soc. Antiq. Ireland, xiv. 313-45, and xv. 402-6).
3. Special Monographs, etc.
Acton Burnell. Hartshorne, C. H., F.S.A. (Archaeol. Journal, ii. 325-38).
Alnwick. Clark, Mediæval Mil. Architecture, i. 175-85.
—— Knowles, W. H., F.S.A., F.R.I.B.A. The Gatehouse and Barbican of Alnwick Castle (Archaeologia Æliana, 3rd ser., v. 286-303).