Opera is My Hobby - In Memoriam: Hermann Prey (series VII, n. 666); A Comparison of Acoustical and Electric Records sung by Famous Operatic Artists (series VII, n. 667), Box: 12, Folder: 56. Personal Papers of James E. Seaver, PP 534. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/163701 Accessed June 24, 2025.