Stop the music, stop the music!
Jethro Burns was NOT a "country" mandolinist, in the sense I think you were using the word.
Certainly, being a native southerner, (though he spent almost all of his professional life in Chicago when not on the road) he had a rural accent and disposition. But he was a jazzer all the way, and a very fine one.
Ya know, the people on this site don't listen to nearly enough vinyl.
For further information, type the name "Steve Goodman" into your browser.
And Homer was no slouch either. He only know one set of barre chords -- ALL of them.