. . "1900 - 1999" . . . "History"@en . . . . . . "Chiefly relate to music theory, concerts, and publications. Correspondents include Wilhelm Furtwängler, Heinrich Jalowetz, René Leibowitz, Artur Schnabel, Alfred Wallenstein, and Klaus and Monika Mann."@en . . . . . . . . "Letters from notable musicians"@en .