I found the story "The Death of Koshchei the Deathless" in Strange Travelers very entertaining. Although I could tell it was based on "fairy tale" material. I didn't recognize that it was from a specific story until I read the note at the end. The title did seem tantalizingly familiar until I got to that point however.
The Red Fairy Book by Andrew Lang is available on line, if anyone is interested in reading the original story Wolfe based his on. It is interesting to see what he kept and what he changed. The Lang version of the story is also interesting in its own right. The story seems to have been cobbled together from bits and pieces and the pieces don't all fit.
This URL should take you to a page that allows you to choose from variously compressed versions of a text file containing The Red Fairy Book:
http://sailor.gutenberg.org/by-title/xx1352.html
This URL is a direct link to download an uncomressed text version of the book (its about 663 kB):
ftp://sailor.gutenberg.org/pub/gutenberg/etext96/rdfry10.txt
William Ansley