. . "Entered from booking ledger and New York Times concert listing and review.\r\n\"Who Makes Music and Where.\" New York Times (1923-), 19 Apr. 1970, p. 103. ProQuest. Web. 29 July 2025.\r\n\"SUMNER TRIO SHOWS INTERPRETIVE FLAIR.\" New York Times (1923-), 21 Apr. 1970, p. 46. ProQuest. Web. 29 July 2025." . . . . "The Sumner Trio" . "1970-04-19T20:30:00"^^ . . "chamber music performance" . .