Quartet Will Play Musical Mozart, Beethoven, and Ravel will be represented on the pro gram of the Coolidge string quar tet in its concert here Monday, April 20, at 8:15 p.m., in the school of music auditorium. .^Quartets by these three com posers will be played by William Kroll and Jack Pepper, violins; David Dawson, viola, and Naoum Benditszky, violoncello, who com prise the quartet. Founded in 1936 under the sponsorship of Elizabeth Sprague Coolidge foundation of the libra ry of congress, Washington, the quartet has played throughout Canada, Mexico, Honolulu, and the United States and are not ed for their radio programs from Washington, D. C. William Kroll, a native New Yorker, began his musical ca reer 'at 10 when he began study • ing under the late Henri Marteau in Berlin. Back in New York he continued his studies under Franz Kneisel at the Institute of Mu sical Art from which he was graduated with highest honors. He was a violinist of the Elshuco Trio and first violin of the South Mountain Quartet before helping to found the Coolidge quartet. Jack Pepper, also American, was a scholarship student at the Eastman school from 1928 until 1930 and also studied with Leo pold Auer. He played for three years with the Los Angeles Phil harmonic under Otto Dlemperer. % David Dawson of Virginia studied at the Juillard school un der Hans Letz and Felix Sal mond. After graduation he be came solo viola of the National Orchestra association under Leon Barzin; later he was a member of the Metropolitan Opera orches tra. Later he was principal viola of the Minneapolis symphony un der Dimitri Mitropoulos. Naoum Benditsky, Russian, at 13 had won a sholarship to the St. Petersburg Imperial Conserv atory, and at 16 was solo cellist of a major Russian orchestra. In *