http://www.harmonx.com/ Harmonx Stuart Hinds sings in a unique, truly contrapuntal style, producing two independent musical lines simultaneously. http://www.innersound.co.uk/ Healing sounds Tibetan & Mongolian overtone chanting; ancestral lines, family fields,healing vibrations workshops. http://www.jillpurce.com/ Jill Purce: The Healing Voice Jill specializes in Mongolian overtone chanting, breathing and chanting techniques. We all have our own note; if you liberate the voice you liberate the human being. http://www.spectralvoices.com/ Jim Cole and Spectral Voices - Harmonic Overtone Singing Information on harmonic singing and Jim Cole and Spectral Voices' unique blendings in vast reverberant spaces to create vocal spacemusic. Includes sound clips, performance updates, and ordering information. http://www.multimania.com/tranquanghai/overtones_index.html Overtones Researches Articles in English and French by Trân Quang Hai and others.