Luciano Berio on Recital for Cathy
1. Letter by Luciano Berio to Cathy Berberian (undated, ca 1972; Cristina Berio's private archive).
2. Interview with John Amis, BBC Radio 3; London, UK première of Recital for Cathy, Roundhouse, March 26, 1973 (audio track at the bottom of the page).