It was, as mentioned before, written by Crawford Howard. Others have modified it to suit their own taste but the 'original' is by C.Howard. I have seen it in print with the credit given as "by Crawford Howard and -----". I have always thought this was a bit cheeky. If you cobbled together a new verse for, say, a Woody Guthrie song would you you let it go into print with this ... "by Woody Guthrie and -----" ?