Nancarrow???s studies use very complex canons and ratios (two voices might progress in a 17-to-19 ratio), and his music has been immensely influential on composers such as Gy??rgy Ligeti and Burt.If I mention Nancarrow, I must also mention Easley Blackwood???s Twelve Microtonal Etudes for Electronic Music Media from 1980, since reissued on CD (Cedille CDR 90000 018).