Question: Which American Professional boxer who retired in 1981 is interviewed for the 2009 documentary Facing Ali?

Context paragraphs:
Archie Moore: Archie Moore (born Archibald Lee Wright; December 13, 1916 – December 9, 1998) was an American professional boxer and the longest reigning World Light Heavyweight Champion of all time (December 1952 – May 1962).  He had one of the longest professional careers in the history of the sport.  Nicknamed "The Mongoose", and then "The Old Mongoose" in the latter half of his career, Moore holds the record for the most career knockouts (132) in boxing history.  Moore was a highly strategical and defensive boxer, with a great chin and bludgeoning power, he ranks #4 on "The Ring"s list of "100 greatest punchers of all time".  Moore is rated by prominent boxing website BoxRec as the 3rd greatest pound-for-pound boxer of all-time.  Moore was also a trainer for a short time after retirement.  He trained boxers such as Muhammad Ali, George Foreman and James Tillis.

Derik Murray: Derik Murray is the founder of Network Entertainment.  He began his career as an advertising photographer and television commercial director before switching his attention to television, film and publishing projects.  His credits include producing the Academy Award shortlisted "Facing Ali", a feature documentary made with Lionsgate Entertainment, and "I Am Bruce Lee", which had its US television premiere on Spike TV where it garnered the highest ratings for a documentary in the network’s history.  Derik also produced "I Am Steve McQueen", produced and co-directed "I Am Evel Knievel", "I Am Chris Farley" (which surpassed "I Am Bruce Lee" ratings for Spike TV), "Johnny Cash - American Rebel" for CMT, and "The Cowboy" for Discovery.  Derik recently produced and directed the feature documentary "I Am JFK Jr." and is executive producing and co-directing the seven-part series "Facing" for National Geographic.  In 2017 he produced the feature film "I Am Heath Ledger".

Leon Spinks: Leon Spinks (born July 11, 1953) is an American former professional boxer who competed from 1977 to 1995.  In only his eighth professional fight, he won the undisputed heavyweight championship in 1978 after defeating Muhammad Ali via split decision, in what was considered one of the biggest upsets in boxing history.  Spinks was later stripped of the WBC title for facing Ali in an unapproved rematch seven months later, which he lost by unanimous decision.

Oh My God (2009 film): Oh My God is a 2009 documentary film by filmmaker Peter Rodger.  The filmmaker asked people across the world the question "What is God?"  Notable figures interviewed include Ringo Starr, Hugh Jackman, David Copperfield, Seal, Bob Geldof, Baz Luhrmann, Jack Thompson, Princess Michael of Kent and Lawrence Blair.

Facing Ali: Facing Ali is a 2009 documentary directed by Pete McCormack about Muhammad Ali (born Cassius Marcellus Clay, Jr. in Louisville, Kentucky) as told from the perspectives of some of the notable opponents he faced during his career: George Chuvalo, Sir Henry Cooper, George Foreman, "Smokin'" Joe Frazier, Larry Holmes (a former sparring partner of Ali), Ron Lyle, Ken Norton, Earnie Shavers, Leon Spinks and Ernie Terrell.

Tony Thornton: Tony Thornton (November 8, 1959 – September 10, 2009, in Camden, New Jersey) was an American professional boxer who died of a motorcycle accident on 10 September 2009.  During his career as a professional boxer, Tony fought three times for the world Super Middleweight Championship.  Tony attended West Chester University of Pennsylvania.

I Am Ali: I Am Ali is a 2014 documentary directed by Clare Lewins.  It covers the life of professional boxer Muhammad Ali.  The film tells his story using personal audio recordings Ali made himself during the 1970s.  Additionally, interviews of friends, family members, and people associated with professional boxing, combined with archival footage of Ali, are used throughout the movie.  Notable appearances in the film include George Foreman, Jim Brown, and Mike Tyson.

Pete McCormack: Pete McCormack (born January 27, 1965) is a Canadian author, filmmaker, screenwriter and musician.  He is best known for directing the Academy Award short-listed documentary Facing Ali and the Leacock Award-nominated novel Understanding Ken.  He is the creator of the HBO Canada documentary television series "Sports on Fire".

Ken Norton: Kenneth Howard Norton Sr. (August 9, 1943 – September 18, 2013) was an American professional boxer who competed from 1967 to 1981, and held the WBC heavyweight title in 1978.  He is best known for his trilogy with Muhammad Ali, in which Norton won the first fight by split decision, and controversially lost the latter two fights by split and unanimous decision, respectively.  Norton also fought a slugfest with Larry Holmes in 1978, narrowly losing a split decision.  Having officially retired from boxing in 1981, Norton was inducted into the International Boxing Hall of Fame in 1992.

Laila Ali: Laila Amaria Ali (born December 30, 1977) is an American former professional boxer who competed from 1999 to 2007.  She is the daughter of legendary boxing champion Muhammad Ali with his third wife, Veronica Porché Ali, and is the eighth of her father's nine children.  During her career, from which she retired undefeated, she held the WBC, WIBA, IWBF and IBA female super middleweight titles, and the IWBF light heavyweight title.

Supporting paragraphs: Facing Ali Ken Norton
Answer: Ken Norton