also puts limits on the number of writers: on films, "Screenplay by", "Teleplay by", and "Written by" credit each can list no more than three writers (or writing teams). Director billing The Directors Guild of America (DGA) requires that a film lists only one director, even if more than one director has worked on the film, with few exceptions, such as for directing teams such as the Coen brothers. If the main credits occur at the beginning, then the director's name is last to be shown before the film's narrative starts, as a result of an agreement between the DGA and motion picture producers in 1939. If all billing is shown at the end, the director's name will be displayed first, immediately followed by the writing credits. In 1980, George Lucas resigned from the DGA after it insisted, against his wishes, that Irvin Kershner, the director of The Empire Strikes Back, be credited at the beginning of the film because the company name Lucasfilm was there; it had previously allowed the original Star Wars (1977), which had a similar opening sequence, to go unchallenged because the writer-director credit (George Lucas) matched the company name Lucasfilm Ltd. Ben-Hur is one of the few MGM films in which the director receives very prominent billing in the posters advertising the movie – the posters state "William Wyler's Production of", although the same credit does not appear in the actual on-screen credits. A similar example is David Lean, whose Doctor Zhivago and Ryan's Daughter both carry the credit "David Lean's Film of" (followed by the title). Stanley Kubrick received prominent title billing from Dr. Strangelove (1964) onwards, and from A Clockwork Orange (1971) he generally received main billing, with the actors only listed in the billing block. Advertising materials for Kubrick's Eyes Wide Shut featured the billing "CRUISE / KIDMAN / KUBRICK". Filmmaker and playwright Tyler Perry always inserts his name into the title of each of his films and television shows. For instance: Tyler Perry's Why Did I Get Married? or Tyler Perry's Meet the Browns. To date, the only film he has not done this with is For Colored Girls, which is an adaptation of the Ntozake Shange play For Colored Girls Who Have Considered Suicide When the Rainbow Is Enuf. In 2004 Robert Rodriguez quit the DGA because he wanted to credit Frank Miller as "co-director" on the film Sin City.