Question: Kelly Willis included a cover of a 1977 song by which country music duo?

Context paragraphs:
Kelly Willis (album): Kelly Willis is the self-titled third album from the Austin, Texas-based singer.  There were a couple of minor Billboard hits in the #63 "Heaven's Just a Sin Away" (covering a 1977 #1 hit for The Kendalls) and the #72 "Whatever Way the Wind Blows."  Also of note is a duet with Kevin Welch, "That'll Be Me."

Ronnie McDowell: Ronald Dean McDowell (born March 25, 1950) is an American country music artist.  He is best known for his 1977 song "The King Is Gone", a tribute to Elvis Presley, who had recently died.  From that single onward, McDowell charted more than thirty Top 40 hits on the "Billboard" country music charts.  Two of his singles – "Older Women" and "You're Gonna Ruin My Bad Reputation" — reached Number One on the country charts, while eleven more reached Top Ten.  He has also released more than twenty studio albums, and has been signed to Curb Records since 1986.

Fading Fast: Fading Fast is a rare EP by country music singer Kelly Willis.  A&M Records originally released the CD as a promotional item, then later issued a limited number of copies for sale only in Texas.  It features recordings with Jay Farrar of Son Volt, and with the band 16 Horsepower.  One of its tracks, "He Don't Care About Me," was written by Willis's husband, country music singer Bruce Robison.

Travelin' Soldier: "Travelin' Soldier" is a song written and originally recorded by American country music artist Bruce Robison in 1996 and again, in rewritten form, in 1999.  It was later recorded by Ty England on his 1999 album, "Highways & Dance Halls".  The first rendition to be issued as a single was by the Dixie Chicks in December 2002, from their album "Home".  It became the group's sixth and final single to reach No. 1 on "Billboard" "Hot Country Singles & Tracks" (now "Hot Country Songs").  A version of the song featuring Natalie Maines of the Dixie Chicks, Bruce Robison and Robison's wife, Kelly Willis, appears on "KGSR's Broadcasts Vol.  13" album.  Aaron Lewis also recorded a cover of the song as a duet with his daughter Zoe on his 2016 album "Sinner".

Bang Bang (Kelly Willis album): Bang Bang is the second of three albums by country music artist Kelly Willis for MCA Records.  It received little attention from country radio, although it was the biggest-selling of the three.  The album includes the "Billboard" minor country hit "Baby Take a Piece of My Heart," which rose to #51 on the charts.

Well Travelled Love: Well Travelled Love is the debut album of American singer Kelly Willis.  It was released in 1990 via MCA Records and produced by Tony Brown.  "I Don't Want to Love You", "River of Love" and "Looking for Someone Like You" were all released as singles from it.  Although none of these charted in the United States, "Looking for Someone Like You" reached #85 on the "RPM" country singles charts in Canada.  Also included on this album is the song "Drive South".  Originally recorded by John Hiatt, it was a #63 single for The Forester Sisters and The Bellamy Brothers, and a #2 county hit for Suzy Bogguss in 1992.

Wrapped (Bruce Robison song): "Wrapped" is a song written by Bruce Robison.  First recorded on his 1998 album "Wrapped", then by Kelly Willis on her 1998 album "What I Deserve", it was later covered by American country-music artist George Strait on his 2006 album "It Just Comes Natural".  It was released on March 19, 2007 as the album's third single; Strait's version of the song was a Top 5 country hit, reaching number 2 on the "Billboard" country charts.

The Kendalls: The Kendalls were an American country music duo, consisting of Royce Kendall (September 25, 1935 – May 22, 1998) and his daughter Jeannie Kendall (born October 30, 1954).  Between the 1960s and 1990s, they released sixteen albums on various labels, including five on Mercury Records.  Between 1977 and 1985, 22 of their singles reached the top 40 on "Billboard"s country singles charts, including three number one hits, "Heaven's Just a Sin Away" (also a No. 69 pop hit), "Sweet Desire", and "Thank God for the Radio"; eight additional singles reached the Top Ten.

The Ashtray Hearts: The Ashtray Hearts are a U.S. band originally from Minneapolis.  The band currently comprises five members, and their music is described as apartment music, a sound that references Americana, folk, and country while embracing the singer-songwriter aesthetic of early 1970s Asylum Records.  The band has toured the U.K. and the U.S., sharing the stage with The New Pornographers, Richard Buckner, Okkervil River, Jesse Sykes, Laura Veirs, Kelly Willis and others.  Music from the Ashtray Hearts was featured in the independent film, "The Be All and End All" (2011).  "The Strangest Light," the band's third LP, was released in January 2013.

Kelly Willis: Kelly Willis (born October 2, 1968) is an American country music singer-songwriter, whose music has been described as alternative country and new traditionalist.

Supporting paragraphs: Kelly Willis (album) The Kendalls
Answer: The Kendalls