Hugo Hasslo, Jussi Bjorling
When there was talk about Jussi Bjorling, my Norwegian singing teacher used to say, "he is the devil himself for singing."
"Hugo Hasslo, Baritone at The Stockholm Opera, Colleague and Cast-comrade of Jussfs: Memories of Jussi,"
Journal of the Jussi Björling Societies of the USA & UK: Vol. 18
, Article 10.
Available at: https://scholarsarchive.byu.edu/jussibjorlingsociety/vol18/iss1/10