Entered from booking ledger and New York Times concert listing and review. WORLD PREMIERE of John Jacob Niles' SPEAK GENTLY TO MY HEART, DEAR ONE "THE WEEK'S OPERA AND CONCERT PROGRAMS." New York Times (1923-), Oct 11 1964, p. 1. ProQuest. Web. 10 Jan. 2024. "Helen Beiderbecke, Soprano." New York Times (1923-), Oct 12 1964, p. 36. ProQuest. Web. 10 Jan. 2024.