Entered from booking ledger and New York Times concert listing and review. "CONCERT AND OPERA PROGRAMS OF THE WEEK." New York Times (1923-), Jan 10 1960, p. 1. ProQuest. Web. 25 May 2022. "Mady Metzger-Ziegler Sings." New York Times (1923-), Jan 12 1960, p. 22. ProQuest. Web. 25 May 2022.