Walter Braunfels, piano pieces op. 31 and 33

[Stefaan]

Hello everybody, I am looking for "Vor- und Zwischenspiele für Klavier, op. 31" and "14 Präludien für Klavier, op. 33" by German composer Walter Braunfels, who died in 1954. I wouldn't mind pursuing them in traditional manner, i. e. buying them, but they are no longer available, though they were once published by Universal Editions as nos. 6623 resp. 7035.