Question: Who were the producers of the 1977 epic war film in which James Caan had a role?

Context paragraphs:
A Bridge Too Far (film): A Bridge Too Far is a 1977 epic war film based on the 1974 book of the same name by Cornelius Ryan, adapted by William Goldman.  It was produced by Joseph E. Levine and Richard P. Levine and directed by Richard Attenborough.

Alien Nation (film): Alien Nation is a 1988 American buddy cop neo-noir science fiction action film directed by Graham Baker.  The ensemble cast features James Caan, Mandy Patinkin and Terence Stamp.  The film depicts the assimilation of the "Newcomers", an alien race settling in Los Angeles, much to the initial dismay of the local population.  The plot integrates the neo-noir and buddy cop film genres with a science fiction theme, centering on a union between a veteran police investigator (Caan) and an extraterrestrial (Patinkin); the first Newcomer detective.  The duo probe a criminal underworld attempting to solve a homicide.

Submarine X-1: Submarine X-1 is a 1968 DeLuxe Color British World War II war film loosely based on the Operation "Source" attack on the German battleship "Tirpitz" in 1943.  In the film James Caan stars as Lt. Commander Richard Bolton, a Canadian, who must lead a group of midget submarines in an attack on a German battleship.

Journey to Shiloh: Journey to Shiloh is a 1968 Technicolor epic western film starring James Caan, Michael Sarrazin, Harrison Ford, Brenda Scott, Albert Popwell, Jan-Michael Vincent, Robert Pine, Noah Beery and directed by William Hale.  As well early starring performances from Caan and Sarrazin, it also features small parts for up-and-coming actors Harrison Ford and Jan-Michael Vincent.

Openfilm: Openfilm was a website for finding and distributing independent film.  Its Advisory Board included members of the film industry, such as James Caan, Robert Duvall, Scott Caan and Mark Rydell, and independent filmmaker Alan Melikdjanian.

A Boy Called Hate: A Boy Called Hate is a 1995 film starring Scott Caan, his father James Caan, Missy Crider, Adam Beach and Elliott Gould.  It was the first film directed by Mitch Marcus, who also wrote the screenplay.

James Caan: James Edmund Caan (born March 26, 1940) is an American actor.  After early roles in "The Glory Guys" (1965), for which he received a Golden Globe nomination, "El Dorado" (1966), and "The Rain People" (1969), he came to prominence in the 1970s with significant roles in films such as "Brian's Song" (1971), "Cinderella Liberty" (1973), "The Gambler" (1974), "Freebie and the Bean" (1974), "Rollerball" (1975), "Funny Lady" (1975), "A Bridge Too Far" (1977), "1941" (1979), and "Chapter Two" (1979).  For his signature role in "The Godfather" (1972), that of hot-tempered Sonny Corleone, Caan was nominated for the Academy Award for Best Supporting Actor and the corresponding Golden Globe.

In the Shadows (2001 film): In the Shadows is a thriller film directed and written by Ric Roman Waugh and starring Matthew Modine, James Caan, Joey Lauren Adams, Lillo Brancato and Cuba Gooding Jr..  It was released in the United States on June 22, 2001.  In the film, Modine plays hit man Eric O'Bryne, who is sent to kill veteran Hollywood stuntman Lance Huston (Caan), falls in love with the target's daughter (Adams) and then decides to become a stuntman himself.

Freebie and the Bean: Freebie and the Bean is a 1974 American action-comedy film about two off-beat police detectives who wreak havoc in San Francisco attempting to bring down a local organized crime boss.  The picture, a precursor to the buddy cop film genre popularized a decade later, stars James Caan, Alan Arkin, Loretta Swit and Valerie Harper.  Harper was nominated for the Golden Globe for New Star of the Year for playing the Hispanic wife of Alan Arkin.  The film was directed by Richard Rush.  An article in Rolling Stone magazine alleged that Stanley Kubrick called "Freebie and the Bean" the best film of 1974.  Arkin and Caan would not appear in another movie together until the 2008 film adaptation of "Get Smart".

Henry's Crime: Henry's Crime is a 2010 American romantic comedy film directed by Malcolm Venville and starring Keanu Reeves, Vera Farmiga, and James Caan.  The film follows Henry (Reeves), who goes to jail for a robbery he did not commit.  Once released, he plans on robbing the same bank with his former cellmate Max (Caan).  The film premiered at the Toronto International Film Festival on September 14, 2010, and was given a limited release in the United States on April 8, 2011.

Supporting paragraphs: James Caan A Bridge Too Far (film)
Answer: Joseph E. Levine and Richard P. Levine