Absolutely wonderful singer, who died far too young. Fortunately there's quite a lot of her recordings available, and I'd particularly recommend a 10" Folkways LP which you can download from the Smithsonian Folkways site. The disc is called Spirituals, Folkways. FA 2038, and she shares it with her cousin Dock Reed. Even now, forty-odd years after I first heard it, it still devastates me.

Also, she's on several Rounder CD reissues of the Library of Congress LP series, if they're still available.
Also, the Alabama CD in Rounder's Deep River of Song series, if it's still available.
Also, she features on several volumes of Rounder's Southern Journey set; the reissues of a set originally on Prestige, drawn from Alan Lomax's 1959 field recording trip of the southern United States. If it's still available.
Also, the Atlantic/WEA 4 CD set, Sounds of the South, which again drew on Lomax's 1959 trip.
Finally, the Alan Lomax produced radio programme, Blues in the Mississippi Night has one or two songs by her.
I think that about covers it. If anyone can think of anything I've missed, do please post.