AP Films or APF (renamed Century 21 Productions in 1966) was a British independent film production company of the 1950s until the early 1970s. The company became internationally known for its imaginative children's action-adventure marionette television series – most significantly Thunderbirds – produced for British ITV network companies Associated-Rediffusion, Granada, ABC and ATV. At its height, the company employed more than 200 staff.[6]
^La Rivière, Stephen (2014) [2009]. "A Wonderland of Stardust: Fireball XL5". Filmed in Supermarionation (2nd ed.). London, UK: Network Distributing. p. 333. ISBN978-0-992-9766-0-6.