Entered from booking ledger and New York Times concert listing and review. According to the review, "The program was a little delayed. Ms. Halozan had forgotten her music. But Mr. Potter, an elderly man who did not disclose his first name, kindly offered "On the Sunny Side of the Street" as prelude, and its jaunty piano-roll figurations – it was an urtext version – set the style and mood." "Who Makes Music and Where." New York Times (1923-), Apr 24 1966, p. 1. ProQuest. Web. 6 Sep. 2024. "Bertha A. Halozan, Mezzo, has a Style Peculiarly Her Own." New York Times (1923-), Apr 30 1966, p. 18. ProQuest. Web. 9 Sep. 2024.