Snow, Joseph T., y Arno Gimber. «Richard Strauss, Stefan Zweig, Joseph Gregor and the Story of the <i>Celestina< i> Opera That Almost Was, With a Bibliographical Appendix of <i>Celestina< I> Operas in the Twentieth Century». Celestinesca, vol. 31, enero de 2021, pp. 133-62, doi:10.7203/Celestinesca.31.20074.