Luise Helletsgruber was an Austrian operatic soprano, who performed at the Vienna State Opera, the Salzburg Festival and the Glyndebourne Festival Opera.
From Wikipedia (https://en.wikipedia.org/wiki/Luise_Helletsgruber) under Creative Commons Attribution CC-BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0/legalcode)