W. Dugdale, Monasticon Anglicanum new edition (James Bohn, London 1846), VI Part 2, p. 898, Langdon, Charter No. 1. (in Latin).
E. Foss, The Judges of England (London 1848), I, at page 185.
Foundation charters in W. Dugdale & R. Dodsworth, Monasticon Anglicanum, sive Pandectae Coenobiorum, 3 Vols (London (Savoy) 1673), III, pp. 74-76. (in Latin).