In the beginning of the episode, when Earth-19 Harrison Wells is handing out the coffee, he mentions that coffee from his Earth "was wiped out by blight", which is exactly what happened to coffee in the alternate universe in Fringe (2008). This is just one of many references that The Flash (2014) has had to that TV show.
On Earth Nineteen, Alfred Hitchcock made a film entitled "Murder on the Titanic". In 1939, Hitchcock gave an interview to a British film journal in which he said that he hoped to make a film about the sinking of the RMS Titanic as his first Hollywood production. However, the film was never made and Rebecca (1940) became Hitchcock's first Hollywood film.
Earth-19 H.R. Wells states that he is a novelist. H.G. Wells is a famous science fiction author who has written stories such as "The Time Machine" and "War of the Worlds", to which many of The Flash's plots are similar.
Julian mentions that he comes from a wealthy English family. In the Harry Potter series, Draco Malfoy, the role for which Tom Felton is most famous, also comes from a wealthy English family.
This episode makes references to Star Wars Episode V: The Empire Strikes Back. Mark Hamill, who plays the Trickster in this show, is most famous for playing Luke Skywalker in the Star Wars saga