aurore, I have a copy of Oak Publications 'We Sahll Overcome' the songs of the Soutern Freedom Movement (1963) I would recommend that if you can get a copy or would be happy to forward anything on

I also have the 'Carry it On' book by Pete Seeger and Bob Reiser - A history in song and picture of the working men and women of America which was published in 1985/6 I think in the UK but covers a much earlier period with a wider remit