Question: are Boulevard Solitude and Moses und Aron both German librettos?
Sentence (from "WDR Rundfunkchor Köln"): The choir premiered works by contemporary composers including Arnold Schoenberg's unfinished opera "Moses und Aron" in 1954, Karlheinz Stockhausen's "Momente", Luigi Nono's "Il canto sospeso", Bernd Alois Zimmermann's "Requiem für einen jungen Dichter" and Penderecki's "St Luke Passion".
Relevant evidence: No