Bravo Charlie. To me the key thing either live or on a recording is to acknowledge your source, and indicate whether you've changed things substantially. Oddly enough, although I find it a bit silly when someone makes a point of telling someone else that they've sung a "wrong" line or word, I get totally pissed-off when someone with an "in your face" attitude wrongly credits a song, simply because they've never taken the time to dig beneath the surface. Everyday of my life since I first heard a "folk" song has been a learning experience, and I expect to keep learning till I croak.

Rick