sentences:  He started writing a series of rhythm studies for his students called Rock Etudes (later, the name was changed to Vocal Rhythm Etudes).These were influenced by African, Indian, and Brazilian music, as well as contemporary classical music, jazz, and funk (particularly the 70s funk of Miles Davis and Herbie Hancock).They have been used in many schools around North America, and he performs at least one of them in all his concerts.