Wonderful scholarship, and fascinating stuff!

Re David el Gnomo's aside:
"I was realy interested to hear that the song in question was based on a Ukraine folk song though - It now goes in with 'Those were the days' and 'The Carnival is over' for me. How many more are there?"

George Gershwin's Summertime is another, according to Denise and Randy Bachman's research for their CBC program Vinyl Tap. The melody is borrowed from a traditional Ukrainian lullaby.