Audio-visual aids to instruction 2026-02-15T17:56:30+03:00 DEBUG: VuFind\ILS\Driver\Folio: Token taken from global cache: eyJhbGciOiJIUzI1NiJ9.eyJzdWIiO... - McKown, Harry C. (Harry Charles), 1892-1963; Roberts, Alvin B. (McGraw-Hill series in education, Harold Benjamin, consulting editor, 1949)