"British National Opera Company at Golders Green". The Musical Times. 69 (1019). Musical Times Publications Ltd: 66–67. 1 January 1928. doi:10.2307/917029. JSTOR917029.
"British National Opera Company at Golders Green". The Musical Times. 69 (1019). Musical Times Publications Ltd: 66–67. 1 January 1928. doi:10.2307/917029. JSTOR917029.