the main part of this song is very similar if not identical to an old traditional song from the Ionian islands in greece.   See from 0:28 in the following link.

http://www.youtube.com/watch?v=rhJrtOmlI4I

I'm Greek and Canadian, and for years I've wondered about this similarity. I have just read that the greek song was recorded/documented around the 1930's, but had existed for a long time before that as a traditional song passed down the generations. My father, born in the 30's, knew it as a child.