- Byron Hoyt Music Company (SF) with online ordering of over 350,000 titles, sophisticated search engines and current item availability. Many of our titles ship within 24 hours.
- The Contemporary A Cappella Society's Almanac and comprehensive directory of a cappella groups.
- Mainely A Cappella - mail order a cappella source.
- Musi-Cal - this link searches for all a cappella events within 100 miles of SF. This is a great service to do one-time or periodic automatic searches for a cappella events.
- Primarily A Cappella - mail order a cappella source.