Entered from booking ledger; flyer, and New York Times concert listing and review. "CONCERT AND OPERA PROGRAMS OF THE WEEK." New York Times (1923-), Mar 16 1958, p. 1. ProQuest. Web. 29 Oct. 2021. "KOECKERT QUARTET MAKES DEBUT HERE." New York Times (1923-), Mar 17 1958, p. 20. ProQuest. Web. 29 Oct. 2021.