The Sonny Terry reference puzzles me. Sonny never to my knowledge did anything remotely like this, and I've heard nearly all of his recordings made from the 1930s onward.

But like the "Blind Lemon" reference way up at the beginning of the thread, it could be a haphazard guess on the part of the person who wrote up the credits. Or Sonny could well have sung a verse resembling something in "I Know You Rider." But his blues were a lot different from it.

Trouble is, antecedent versions of blues are not like antecedent versions of other kinds of songs. They're not like Barbara Allan or John Henry. Blues (apart from ballad blues like Bessie Smith's "Back Water Blues") are assembled on the spot out of often disconnected "floating verses" that may or may not fall into a coherent story.

To show that one blues descended from another, you have to lean a lot harder on melody, sound, overall theme, and the entire text, not just part of it. So if you find a verse or two from "I Know You Rider" in another song or several other songs, that shows commonality of verses, but tells you nothing about their relatedness otherwise.

That's a capsule statement of blues derivation or the lack thereof. Hope that helps separate the sheep from the goats...wheat from the tares...whatever.

Bob