Folk Music Source

Hello everyone.This is my first attempt at publication and I've run into a snag. I want to submit an arrangement of a folk song (The Water is Wide) for publication. The company wants me to submit a source for this folksong. The problem is, I learned this folksong at my mother's knee. I know that this song is a folk song, not a song written by anyone. Wikipedia agrees with me. Unfortunately, I don't know if Wikipedia or my mom will be considered credible sources to a publisher. So where do I go to find a source for this text and melody? Many thanks

Here's a detailed history of that tune for you:  http://www.justanothertune.com/html/wateriswide.html

But I don't know the historian who wrote it to know if they are credible, but if you can find multiple sources saying the same thing, that should do it.  Look at other people's arrangements and see who they cite as the source.  List those citations.  Again, you get enough independent sources saying the same thing, footnote them all appropriately and that should be fine.  It's a very popular tune, so see what other people did with the same question.  See what the leading music historians say about it.  If someone has heard of them, their answer has weight, since the big historians have done the primary source research.  Borrow their sources from their footnotes.  Be a good little scholar.  This is the age of the internet, so this isn't hard information to find, if you just ask the right question of google.  Cite your sources in proper form like a research paper.  (:

You can't use Wikipedia as a source.

You use the sources used for the wikipedia article.

Duh.