I saw the pic on your auction. The lady playing the autoharp on the left of the photo is Mother Maybelle Carter. The second woman in the photo is June Carter her daughter that later married Johnny Cash ad I will have to check on the other two but they should be the other Carter sisters. I think this photo was taken at the Clinch Mountain Jamboree. It would have been in the mid to late 50's I worked with a lot of country and bluegrass artist for many years including the Carter family . The husband of Mother Maybelle was A.P. Carter who wrote The famous song Wildwood Flower for her to play on the autoharp she is holding in the pic. I will look at my photo albums and see which of the girls the other are.