Now THAT'S a resource!! Massive thanks to you Azizi, for finding it and posting the link to it. One of my vocal heroes (heroine?) is the late, incredible English blues singer Jo Ann Kelly (1944 — 1990)
Bonnie Riatt said of her "It was hard to do "Walking Blues" for instance, but I was not born with a voice like Mavis Staples or Jo Ann Kelly."
listen to her

here Louisiana Blues

and here Rolling and Tumbling

Charlotte Olivia Robertson (Ms)