Cotton Nero A.x. Project. Murray McGillivray of the University of Calgary and the British Library have created an online digital facsimile of the Gawain ms. Cotton Nero A. x.
Ross G. Arthur. Medieval Sign Theory and Sir Gawain and the Green Knight. University of Toronto Press: Toronto, 1987. Reprinted
Jonathan Glen. "Notes on Sir Gawain and the Green Knight."
Ross G. Arthur. Sir Gawain and the Green Knight Edited by Ross G. Arthur. In Parentheses Publications: Cambridge, Ontario. 1999.
Charles MacQuarrie. "From Manannán to Bercilak: The Green Knight and the Gaelic Otherworld-god-in-disguise." Studeyrys Manninagh 1.3 http://www.manxstudies.ac.im (2003).
R. Allen Shoaf. "The 'Syngne of Surfet' and the Surfeit of Signs in Sir Gawain and the Green Knight. In The Passing of Arthur: New Essays in Arthurian Tradition, ed. Christopher Baswell and William Sharpe (New York: Garland, 1988), pp. 152-69.
Jessie L. Weston. Trans. Sir Gawain and the Green Knight.
Sir Orfeo. The Auchinleck Manuscript. Eds David Burnley and Alison Wiggins. National Library of Scotland Advocates' MS 19.2.1. This is a digital edition, with manuscript images, of the entire manuscript, hosted by the National Library of Scotland.
Sir Orfeo TEAMS edition edited by Anne Laskaya and Eve Salisbury.
Sir Orfeo. Ed. George Shuffelton. Codex Ashmole 61: A Compilation of Popular Middle English Verse. Kalamazoo, Michigan: Medieval Institute Publications, 2008. This is the version of Sir Orfeo from the Ashmole Ms.
Sir Orfeo. Norton Anthology of English Literature. This is a .pdf file of the lightly modernized, glossed edition of Sir Orfeo that used to be in the Norton Anthology of English Literature Vol. I.