In the second flashback scene, where the 13 year old Julián discovers that he is surrounded by Benito García and other gunmen at the service of Don Artemio, the way that is is revealed, with the bus leaving and showing the gunmen behind, is in homage to the Sergio Leone movie, when the train leaves and reveals the Charles Bronson character behind. This reference came from the early drafts of the screenplay, without quoting the Leone's movie specifically.
The title of the film quotes (in Spanish) the title of Spielberg's film. Both films are about the rescue mission of an American soldier trapped in a foreign country.
