Question: How long was the concert career of the woman that is speculated to be the frustrated love inspiration of Brahms' Liebeslieder Walzer, Op. 52?
Sentence (from "List of Liebeslieder Walzer stagings"): This is a chronological list of stagings of New York City Ballet co-founder and balletmaster George Balanchine's Liebeslieder Walzer, made to the eponymous music by Brahms.
Relevant evidence: No