Question: Robert Zemeckis and Martin Ritt, are of which nationality?

Context paragraphs:
Starlight Theatre (TV series): Starlight Theatre is a 30-minute American anthology series that aired on CBS from 1950–51.  Forty-nine episodes aired.  Season two alternated weekly with "The George Burns and Gracie Allen Show".  Guest stars that appeared include Julie Harris, Barry Nelson, Eve Arden, George Reeves, John Forsythe, Mary Sinclair, Jean Stapleton, Melvyn Douglas, Jackie Cooper, and Franchot Tone.  Among its directors were Martin Ritt, Yul Brynner, Curt Conway, and Robert Stevens.

Five Branded Women: Five Branded Women is a 1960 Italian-American international co-production film directed by Martin Ritt and produced by Dino De Laurentiis.  It featured an international cast including Silvana Mangano, Barbara Bel Geddes, Jeanne Moreau and Vera Miles and was Ritt's only war movie, set during the Nazi occupation of Yugoslavia.  Film was shot in Italy and Austria (Klagenfurt).

Martin Ritt: Martin Ritt (March 2, 1914 – December 8, 1990) was an American director and actor who worked in both film and theater.  He was born in New York City.

End of the Game: End of the Game (German: Der Richter und sein Henker) is a 1975 DeLuxe Color German political thriller drama film directed by Maximilian Schell and starring Jon Voight, Jacqueline Bisset, Martin Ritt and Robert Shaw.  Co-written by Friedrich Dürrenmatt, the film is an adaptation of his 1950 crime novella "The Judge and His Hangman" (German: "Der Richter und sein Henker").  Dürrenmatt also appeared in the film, and Donald Sutherland played the role of the corpse of "Ulrich Schmied".  German silent film actress Lil Dagover made her last screen appearance before retirement in the film.

Edge of the City: Edge of the City is a 1957 American film-noir drama film directed by Martin Ritt, starring John Cassavetes and Sidney Poitier.  It was Ritt's debut film as a director.  Robert Alan Aurthur's screenplay was expanded from his original script, staged as the final episode of "Philco Television Playhouse", "A Man Is Ten Feet Tall" (1955), also featuring Poitier.

Robert Zemeckis: Robert Lee Zemeckis (born May 14, 1952) is an American filmmaker and screenwriter frequently credited as an innovator in visual effects.  Credited as "one of the greatest visual storytellers in filmmaking", he first came to public attention in the 1980s as the director of "Romancing the Stone" (1984) and the science-fiction comedy "Back to the Future" film trilogy, as well as the live-action/animated comedy "Who Framed Roger Rabbit" (1988).  In the 1990s he diversified into more dramatic fare, including 1994's "Forrest Gump", for which he won an Academy Award for Best Director.  The film itself won Best Picture.  The movies he has directed have ranged across a wide variety of genres, for both adults and families.

The Outrage: The Outrage (1964) is a remake of the 1950 Japanese film "Rashomon", reformulated as a Western.  It was directed by Martin Ritt and is based on stories by Ryūnosuke Akutagawa.  Like the original Akira Kurosawa film, four people give contradictory accounts of a rape and murder.  Ritt utilizes flashbacks to provide these contradictory accounts.

Part 2, Sounder: Part 2, Sounder is a 1976 American drama film directed by William A. Graham.  It is the sequel to the 1972 Oscar-nominated film "Sounder", which in turn is based on William H. Armstrong's Newbery Award-winning novel of the same name.  Although Lonne Elder III and Robert B. Radnitz returned as screenwriter and producer respectively, neither Martin Ritt nor any of the cast members from the first film participated in the sequel, with the exception of Taj Mahal, who reprised his role as Ike and returned as composer.  According to Bob McCann, the film was "barely released."

Hud (1963 film): Hud is a 1963 Western film directed by Martin Ritt and starring Paul Newman, Melvyn Douglas and Patricia Neal.  It was produced by Ritt and Newman's recently founded company, Salem Productions, and was their first film for Paramount Pictures.  "Hud" was filmed on location on the Texas Panhandle, including Claude, Texas.  Its screenplay was by Irving Ravetch and Harriet Frank, Jr. and was based on Larry McMurtry's 1961 novel, "Horseman, Pass By".  The film's title character, Hud Bannon, was a minor character in the original screenplay but was reworked as the lead role.  With its main character an antihero, "Hud" was later described as a revisionist Western.

Stanley &amp; Iris: Stanley & Iris is a 1990 American romantic drama film directed by Martin Ritt and starring Jane Fonda and Robert De Niro.  The screenplay by Harriet Frank, Jr. and Irving Ravetch is loosely based on the novel "Union Street" by Pat Barker.

Supporting paragraphs: Robert Zemeckis Martin Ritt
Answer: American