The descriptive note comes from item B0082 in :
Cowden, Robert H.
Concert and opera singers
A bibliography of biographical materials
Compiled by Robert H. Cowden
Westport, Connecticut: Greenwood Press, c1985, 278 p.
This is what Robert H. Cowden had to say:
Personal and revealing articles written by twenty-eight singers who were famous in Germany before the Second World War List
© Robert H. Cowden
(c) 2022. Frank Greene. All rights reserved.