List all the voice actors in the movie directed by Ben Sharpsteen which was released on February 9, 1940.
Ben Sharpsteen refers to director = 'Ben Sharpsteen'; released on February 9, 1940 refers to release_date = 'Feb 9, 1940';
SELECT T2.`voice-actor` FROM director AS T1 INNER JOIN `voice-actors` AS T2 INNER JOIN movies_total_gross AS T3 ON T1.name = T2.movie AND T2.movie = T3.movie_title WHERE T1.director = 'Ben Sharpsteen' AND T3.release_date = 'Feb 9, 1940' AND T2.`voice-actor` != 'None' GROUP BY T2.`voice-actor`