Close Encounters of the Third Kind
From Tardis Wiki, the free Doctor Who reference
Close Encounters of the Third Kind was released in 1977. It led to greater interest in aliens and an increase in the number of UFO believers.
Inspector Graham Stevens had a blown-up still from Close Encounters of the Third Kind in his office. It depicted lights flying over a group of people holding up signs that said 'Stay and Be Friendly'. (PROSE: Cat's Cradle: Witch Mark)
The film was mentioned in a document on the wall of Sarah Jane Smith's attic at 13 Bannerman Road. (TV: Invasion of the Bane)