Very recent source containing authoritative annotated bibliographies. There are currently only about 100 entries for music, but you can cross search other subject areas in this Oxford series, including the Oxford bibliographies for Cinema Studies and Art History.
European dissertations, primarily from Germany, Austria, and Switzerland
Music and the technological imagination in the Weimar Republic: Media, machines, and the new objectivity Scheinberg, Erica Jill. University of California, Los Angeles, ProQuest, UMI Dissertations Publishing, 2007. 3302539.
Instruments for new music: Sound technology and modernism in the Weimar Republic Patteson, Thomas W.. University of Pennsylvania, ProQuest, UMI Dissertations Publishing, 2013. 3566465.
The operas of Hindemith, Krenek, and Weill: Cultural trends in the Weimar Republic, 1918-1933 Babcock, Renee Elizabeth. The University of Texas at Austin, ProQuest, UMI Dissertations Publishing, 1996. 9719291.
Silent opera: The manifestation of silent film techniques in opera during the Weimar Republic Monchick, Alexandra Shernan. Harvard University, ProQuest, UMI Dissertations Publishing, 2010. 3435309.
The jazz republic: Music, race, and American culture in Weimar Germany Wipplinger, Jonathan Otto. University of Michigan, ProQuest, UMI Dissertations Publishing, 2006. 3224787.