"Deutschlandradio Kultur." Compact disc (ADD). Program notes in English in container. Recorded Jan. 26, 1959, RIAS Studio 7, Berlin (op. 23), Oct. 31, 1967, Saal 2, WDR, Köln (op. 59), Mar. 15, 1967, Hochschule für Musik, Berlin (op. 58) and Dec. 3, 1067, Studio Lankwitz, RIAS, Berlin (remainder) Martha Argerich, piano.