Negro spirituals are best preserved through live performance, archived scores or recordings, and published bibliography. A few sources are listed here:
Classical Vocal Reprints_ Recital/Concert Music Scores (http://www.classicalvocalrep.com/)
Jacqueline Butler Hairston_ Composer/Arranger/Pianist (http://www.jbhproductions.com/)
Videmus _ African American Music Source (http://www.videmus.org/)
Kevin J. Miller_ Pianist/Collaborator/Coach (http://www.kevinmillerpiano.com/)
The Spirituals Project at University of Denver (https://www.du.edu/ahss/lamont/outreach-alumni-summer-acad/spirituals-project/)
The American Spiritual Ensemble (http://www.americanspiritualensemble.com/)
Hal Leonard Music Print Publisher (https://www.halleonard.com)
GIA Sacred Music Resources (http://www.giamusic.com/)