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In page Mickey Mouse:

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Steamboat Willie was first released on November 18, 1928, in New York.[2][3] It was co-directed by Walt Disney and Ub Iwerks. Iwerks again served as the head animator,[4] assisted by Les Clark,[5] Johnny Cannon, Wilfred Jackson and Dick Lundy.[citation needed] This short was a nod to Buster Keaton's Steamboat Bill, Jr.,[4][6] released earlier that year. Although it was the third Mickey cartoon produced, it was the first to find a distributor, and thus is considered by The Disney Company as Mickey's debut. It also featured some design refinements, and included the use of a bouncing ball on the film print to allow conductors and musicians to match the tempo of their music with the film.[3][4]