Companion to her study of Tolkien’s use of the Andrew Lang fairy tale collections (in #99/100) with a piece on how Lewis used them as well, but tended to look favorably on and use more modern fantasy sources than Tolkien.
"Watchful Dragons and Sinewy Gnomes: C.S. Lewis's Use of Modern Fairy Tales,"
Mythlore: A Journal of J.R.R. Tolkien, C.S. Lewis, Charles Williams, and Mythopoeic Literature: Vol. 30
, Article 8.
Available at: http://dc.swosu.edu/mythlore/vol30/iss3/8