Hedy Graf
... that Hedy Graf performed soprano parts in premieres of oratorios by Swiss composers?
... that <b id="mwBis"><a href="./Hedy_Graf" id="mwBiw" rel="mw:WikiLink" title="Hedy Graf">Hedy Graf</a></b> performed soprano parts in premieres of <a href="./Oratorio" id="mwBi0" rel="mw:WikiLink" title="Oratorio">oratorios</a> by Swiss composers?