• O'Donovan 1972: O'Donovan, M. A., 'An Interim Revision of Episcopal Dates for the Province of Canterbury, 850–950, I', Anglo-Saxon England 1 (1972), 23–44. See cited charters
  • O'Donovan 1973: O'Donovan, M. A., 'An Interim Revision of Episcopal Dates for the Province of Canterbury, 850–950, II', Anglo-Saxon England 2 (1973), 91–113. See cited charters
  • O'Donovan, Sherborne: O'Donovan, M. A., ed., The Charters of Sherborne, Anglo-Saxon Charters (Oxford, 1988), 3. See cited charters
  • O'Neill 1986: O'Neill, P. P., 'A Lost Old English Charter Rubric: the Evidence from the Regius Psalter', Notes and Queries 231 (1986), 292–94. See cited charters
  • O.S. Facs.: Sanders, W. B., ed., Facsimiles of Anglo-Saxon Manuscripts, 3 vols (Southampton, Ordnance Survey, 1878-1884). See cited charters
  • Oleson 1955: Oleson, T. J., The Witenagemot in the Reign of Edward the Confessor (London, 1955). See cited charters
  • Oleson 1956: Oleson, T. J., 'review of Stenton, Anglo-Saxon England, 2nd edn', Speculum 31 (1956), 202–03. See cited charters
  • Oliver 1861: Oliver, G., Lives of the Bishops of Exeter (Exeter, 1861-1867). See cited charters
  • Oliver, Beverley: Oliver, G., The History and Antiquities of the Town and Minster of Beverley (Beverley, 1829). See cited charters
  • Oliver, Monasticon: Oliver, G., Monasticon Dioecesis Exoniensis (Exeter, 1846). See cited charters
  • Olson 1989: Olson, L., Early Monasteries in Cornwall (Woodbridge, 1989). See cited charters
  • Oppermann 1928: Oppermann, O., Die älteren Urkunden des Klosters Blandinium und die Anfänge der Stadt Gent (Utrecht, 1928). See cited charters
  • Orme 1989: Orme, N., 'The History of Brampford Speke', Transactions of the Devonshire Assocation 121 (1989), 53–86. See cited charters
  • Ortenberg, English Church: Ortenberg, V., The English Church and the Continent in the Tenth and Eleventh Centuries: Cultural, Spiritual, and Artistic Exchanges (Oxford, Oxford University Press, 1992), pp. xvii, 328 pp. ill.. See cited charters
  • Orwin 1938: Orwin, C. S., and C. S. Orwin, The Open Fields (Oxford, 1938). See cited charters
  • Owen 1979: Owen, G. R., 'Wynflæd's Wardrobe', Anglo-Saxon England 8 (1979), 195–222. See cited charters