iron axe -- I came across one of last year's notebooks that I carry with me when attending conferences and lectures which has notes I took at a speech delivered by UCLA Prof. Joseph NAgy (Ph.D. in Celtic Languages and Literatures from HArvard) entitled, "Robin Hood's 'Irish Knife.'"
It's a scholarly examination of Child Ballad 118, "Robin Hood and Guy of Gisbourne." You can see we are already in the area of cross cultural influence.
Some of the references he included are:
A. L. Lord, The Singer Resumes the Tale
D. E. Bynum, The Daemon in the Wood: A Study of Oral Narrative Patterns
E. A. Gray, "Cath Maige Tuired: Myth and Structure," from two editions of the scholarly journal Eigse, 18 and 19.
His own book, The Wisdom of the Outlaw: The Boyhood Deeds of Finn in Gaelic Narrative Tradition.
And an article Nagy contributed to editor Stephen Knight's, Robin Hood: An ANthology of Scholarship and Criticism, entitled, "The Paradoxes of Robin Hood."
There is R.B. Dobson's and John Taylor's (eds.), Rymes of Robin Hood: An Introduction to the English Outlaw,"
and two web sites:
http://lib.rochester.edu/camelot/rh/rhaumenu.htm and
http://emc.english.ecsb.edu/ballad_project/
But, wait! There's more!
Edited by Helen Phillips, Robin Hood: Medieval and Post-Medieval contains three articles of interest:
R. F. Green, "The Hermit and the Outlaw: New Evidence for Robin Hood's Death?"
T. S. Jones, "'Oublie ai chevalrie': Tristan, MAlory and the Oulaw-Knight"
Derek Pearsall, "Little John and the Ballad of Robin Hood and the Monk"
(this is an Irish book and therefore expensive. Frankly, you need access to a university library or an academic used book store for most of this stuff.)
And, as if that isn't enough, you also get with this bibliography:
Gerald of Wales, Topographia Hiberniae (trans. John O'Mara)
Jaan Puhvel, Comparative Mythology
D. S. Thomson (ed) Branwen eurch Lyr (trans. P. K. ford, THe Mabinogi and Other Welsh Tales)
W. Stokes, "Find and the Phantoms," Revue Celtique 7
(Find is an alternate spelling for Finn)
Since this is already a great deal of material, I will summarize my lecture notes in another post.