Hanna-Barbera was a co-production company for seasons 1-4 of the Powerpuff Girls original series. It has also produced many animated hits such as Yogi Bear, Tom & Jerry, Top Cat, The Flintstones, Hong Kong Phooey, The Jetsons and Scooby-Doo. It was founded by the award-winning cartoon creators William Hanna and Joseph Barbera. The company shut down in 2001 before Hanna's death and since then, the rest of the show was produced by Cartoon Network Studios. Many IPs of Hanna-Barbera now belong to Warner Bros. although several of their films in the 90s were released by Universal.