One book that you should definitely look into is Slave Songs of the United States Published in 1867 and republished some years back, this is a good collection of the songs in their original forms. Digital Copy Here This book is a truly important look into the study of Slave Music, and slave culture overall. As well as being the first book published on African American music of any kind. Looking at slave music is vitally important not only to understanding current African-American culture, but American culture as a whole. These spirituals would form the basis for the entire musical genre of Gospel but heavily contributed to the Blues, Folk, and early Rock and Roll.

Edit: Shite grammar.