Question: What is the date of death of Cathy Berberian's husband?
Sentence (from "Cathy Berberian"): She interpreted contemporary avant-garde music composed, among others, by Luciano Berio, Bruno Maderna, John Cage, Henri Pousseur, Sylvano Bussotti, Darius Milhaud, Roman Haubenstock-Ramati, and Igor Stravinsky.
Relevant evidence: Yes