www.harmonicwhirlies.com 
(musical instruments created and manufactured by Sarah Hopkins)

www.australianmusiccentre.com.au/artists/hopkins-sarah

www.mortonmusic.com 
(Sarah's choral music publishers)

www.newalbion.com/artists/hopkinss/  

www.annenorman.com 
(Anne Norman, shakuhachi player and composer)

www.margaretbrandman.com 
(Margaret Brandman, composer and music educator)

www.tranquanghai.com 
(harmonic overtone singing)