Recorded by Süddeutscher Rundfunk, Stuttgart (tracks 3 and 4 from a concert in Stuttgart, June 22, 1975).
With a 14-page booklet with notes in German and English.
Dates of composition: Sonata XIII for prepared piano (1946-48); Music for Marcel Duchamp (1951); Song Books I-II (1970-72); Empty Words III (1974-75)
(P) 1976/1991 Schott Wergo Music Media GmbH, Mainz, Germany
(C) 1991 Schott Wergo Music Media GmbH, Mainz, Germany