"Founded in 1959, the ACDA is a nonprofit music-education organization whose central purpose is to promote excellence in choral music through performance, composition, publication, research, and teaching."
Formed in In 1896, the American Federation of Musicians of the United States and Canada is the self-proclaimed "largest organization in the world representing the interests of professional musicians."
ChoralNet
Includes information on composers, music theory, voice and performance advice, chorus management, recording guides, rehearsal techniques, and concerts in English, French, Spanish, and German.