Question: What movie was the music of Llewyn Davis thought to have descended from?
About the article "Inside Llewyn Davis", section "Music".

Candidate passages:
In February 1961, Llewyn Davis (Oscar Isaac) is a struggling folk singer in New York City's Greenwich Village.
His musical partner, Mike Timlin, has committed suicide; his recent solo album "Inside Llewyn Davis" is not selling; he has no money and is sleeping on the couches of friends and acquaintances.
After performing in the Gaslight Cafe, Llewyn is beaten up by a shadowy suited man for heckling the previous night.
He sleeps at the apartment of his older friends, the Gorfeins.
When he leaves the next morning, the Gorfeins' ginger cat escapes.
Llewyn takes the cat to the apartment of his friends Jim (Justin Timberlake) and Jean (Carey Mulligan) Berkey.
Jean tells him she is pregnant, and fearing that Llewyn may be the father, asks him to pay for an abortion.
After he sleeps on their couch, the Gorfeins' cat escapes again.
On Jim's invitation, Llewyn, as part of the "John Glenn Singers", records a novelty song with Jim and Al Cody (Adam Driver).
Needing money immediately, Llewyn agrees to $200 with no royalties.
At the gynecologist's office, Llewyn sets up Jean's appointment and discovers that a previous girlfriend, whose abortion he also paid for, decided to keep the baby and move to Akron without telling him.
Llewyn and Jean argue about his lack of direction.
He spots what he believes to be the Gorfeins' cat and returns it that evening.
Asked to play after dinner, he reluctantly performs "Fare Thee Well", a song he had recorded with his deceased partner Mike.
When Mrs. Gorfein starts to sing Mike's harmony, Llewyn snaps.
Mrs. Gorfein leaves the table crying, then returns with the cat, having realized that it is not theirs.
Llewyn leaves with the cat.
Llewyn rides with two musicians driving to Chicago: the laconic beat poet Johnny Five (Garrett Hedlund) and the odious jazz musician Roland Turner (John Goodman).
At a roadside restaurant, Roland collapses from a heroin overdose.
The three stop on the side of the highway to rest.
When a police officer tells them to move on, Johnny resists and is arrested.
Without the keys, Llewyn abandons the car, leaving the cat and the unconscious Roland behind.
In Chicago, Llewyn auditions for Bud Grossman (F. Murray Abraham).
Grossman says Llewyn is not suited to be a solo performer but suggests he might incorporate him in a new trio he is forming.
Llewyn rejects the offer and hitchhikes back to New York.
Driving, he hits what he fears may be the same cat.
In New York, he pays $148 in back dues to rejoin the merchant marine union, and visits his ailing father.
Llewyn searches for his seaman's license so he can ship out with the merchant marines, but his sister has thrown it out.
At the Gaslight, Pappi claims he had sex with Jean.
Llewyn becomes upset (presumably at feeling he was swindled by Jean for abortion money) and heckles a woman as she performs.
He goes to the Gorfeins' apartment, where they graciously welcome him.
He is amazed to see that their actual cat, named Ulysses, has found his way home.
The scene from the beginning of the film then replays.
Llewyn performs at the Gaslight.
Pappi teases him about his heckling the previous evening and tells him that a friend is waiting outside.
As Llewyn leaves the building, a young and unknown Bob Dylan takes the stage and begins to sing.
Behind the Gaslight, Llewyn is beaten by the shadowy suited man for heckling the previous night's performer, his wife.
He watches as the man leaves in a taxi and quietly bids him "au revoir". 
Critical response.
Rotten Tomatoes gives the film a score of 94% Certified Fresh based on 230 reviews, with an average score of 8.5/10.
The site's consensus states: "Smart, funny, and profoundly melancholy, "Inside Llewyn Davis" finds the Coen brothers in fine form."
On Metacritic, which assigns a normalized rating out of 100 based on reviews from critics, the film has a score of 92 (indicating "universal acclaim") based on 47 reviews.
Writing for "The Village Voice", Alan Scherstuhl praised the Coen brothers' film: "While often funny and alive with winning performances, "Inside Llewyn Davis" finds the brothers in a dark mood, exploring the near-inevitable disappointment that faces artists too sincere to compromise--disappointments that the Coens, to their credit, have made a career out of dodging.
The result is their most affecting film since the masterful "A Serious Man"."
Todd McCarthy of "The Hollywood Reporter" called the film "an outstanding fictional take on the early 1960s folk music scene," praising the "fresh, resonant folk soundtrack" and Oscar Isaac's performance that "deftly manages the task of making Llewyn compulsively watchable.
"Folk singers, however, have criticized the movie for misrepresenting the friendliness of the Village folk scene of the time.
Terri Thal, Dave Van Ronk's ex-wife, said, "I didn't expect it to be almost unrecognizable as the folk-music world of the early 1960s."
Suzanne Vega said "I feel they took a vibrant, crackling, competitive, romantic, communal, crazy, drunken, brawling scene and crumpled it into a slow brown sad movie."
The movie was also criticized for the fact that, although it was to some extent based on the memoir of Dave Van Ronk, the film portrayed a character very much at odds with the real Van Ronk, usually described as a "nice guy".
However, at a press interview before the film was premiered at Cannes, the Coens had stated that the character itself was very much an original creation, and that the music was the major influence they'd drawn from Van Ronk. 
Dave Van Ronk's music served as a starting point for the Coens as they wrote the script, and many of the songs first designated for the film were those he had recorded.
Van Ronk co-author Elijah Wald said that the character of Llewyn Davis "is not at all Dave, but the music is.” (The cover of Davis's solo album, "Inside Llewyn Davis", resembles that of "Inside Dave Van Ronk".
Both feature the artist in a doorway, wearing a tweed jacket and smoking a cigarette.)
Other songs emerged in conversations between the Coens and T-Bone Burnett, who produced the music in association with Marcus Mumford.
Burnett previously worked with the Coens on the music and soundtrack for "The Big Lebowski" and "O Brother, Where Art Thou?
", the latter of which sold about 8 million copies in the United States.
The Coens viewed the music in the "Llewyn Davis" as a direct descendant of the music in "O Brother.
"The humorous novelty song "Please Mr. Kennedy", a plea from a reluctant astronaut, appears to be a fourth generation derivative of the 1960 song "Mr. Custer", also known as "Please Mr. Custer", about the Battle of the Little Bighorn, sung by Larry Verne and written by Al DeLory, Fred Darian, and Joseph Van Winkle.
A Tamla-Motown single followed in 1961: "Please Mr. Kennedy (I Don't Want to Go)", a plea from a reluctant Vietnam War draftee, sung by Mickey Woods and credited to Berry Gordy, Loucye Wakefield and Ronald Wakefield.
In 1962 using a similar theme, The Goldcoast Singers recorded "Please Mr. Kennedy" on its "Here They Are "album, with writing credits to Ed Rush and George Cromarty.
The Llewyn Davis version credits Rush, Cromarty, Burnett, Timberlake, and the Coens.
Isaac, Timberlake, Mulligan, Driver and others performed the music live.
The exception was "The Auld Triangle", which was lip-synced, with Timberlake singing bass.
(Timberlake's vocal range was on display in the film.
Critic Janet Maslin, listening to a soundtrack recording, confused Timberlake's voice with Mulligan's, which she thought resembled that of Mary Travers.)
Jim and Jean, as well as other husband and wife folk duos of the 1960s (such as Ian and Sylvia, and Richard and Mimi Fariña), were described as being inspirations for the fictional characters "Mitch and Mickey" of the 2003 spoof movie about folk music entitled "A Mighty Wind".
They are also the likely inspiration for the husband-wife folk-singing duo also called Jim and Jean in the Coen Brothers film, "Inside Llewyn Davis".
Jean Ray was the inspiration for Neil Young's song, Cinnamon Girl, as verified by her brother Brian Ray, and perhaps other songs as well.
Jean Ray said, "Neil Young's song 'Cowgirl in the Sand' came from a visit he made to me and my family living on the beach."
George Cromarty (September 15, 1941 – February 12, 1992) was an American folk guitarist and singer.
He is best known as the co-writer, with Ed Rush, of the song "Plastic Jesus", though he went on to record three albums of solo guitar music in the 1970s and 1980s.
The Folk Music Sourcebook likened his playing style to John Fahey's, and George Winston cites Cromarty as a musical influence.
His music has been heard on the soundtracks of many films, including the Coen brothers' "Inside Llewyn Davis."
The "Columbia record exec" in "Inside Llewyn Davis" was named "Mr. Cromarty" in honor of Cromarty.