Question: Who covered the song "Thank God I'm a Country Boy" written by John Martin in an album released in 2003?
Context: "Thank God for Believers" is a song co-written by Mark Alan Springer, Roger Springer and Tim Johnson and was recorded by the American country music singer Mark Chesnutt.  It was released in July 1997 as the title track and first single from his album "Thank God for Believers".  It peaked at number 2 on the U.S. "Billboard" Hot Country Singles & Tracks chart and number 7 on the Canadian "RPM" Country Tracks chart. "Thank God I'm a Country Boy", also known as "Country Boy", is a song written by John Martin Sommers and recorded by American singer/songwriter John Denver. Outskirts of Town is the tenth studio album released by the American country music band Sawyer Brown, released in 1993 on Curb Records.  The third and final album of their career to receive RIAA gold certification, it produced four hit singles on the "Billboard" country charts: "Thank God for You" (the band's third and final #1), "The Boys and Me" (#4), the title track (#40), and "Hard to Say" (#5).  A dance mix of "The Boys and Me" is also included as a bonus track. "Country Boy" is a song written by Tony Colton, Albert Lee, and Ray Smith of the British band Heads Hands & Feet, and recorded by American country music artist Ricky Skaggs.  It was released in February 1985 as the second single and title track from the album "Country Boy".  The song was Ricky Skaggs' ninth number-one country hit.  The single went to number one for one week and spent a total of thirteen weeks on the country chart. Christmas is the seventh country studio album by the Oak Ridge Boys, released in 1982.  It is a holiday / Christmas album released via MCA Records.  The album produced one single in "Thank God for Kids", which made number three on the Hot Country Songs charts. Yes!  is the second studio album released by country music artist Chad Brock.  Lead-off single "A Country Boy Can Survive (Y2K Version)", featuring George Jones and Hank Williams, Jr., is a rewritten version of Williams' hit "A Country Boy Can Survive", rewritten to address the Y2K problem.  This song peaked at #30 on the country charts in late 1999.  Following it were the title track, which became Brock's only Number One hit in mid-2000, and finally "The Visit" at #21. Thank God for Believers is the seventh studio album released by American country music artist Mark Chesnutt.  His third album for Decca Records, it produced four singles on the "Billboard" Hot Country Songs charts between 1997 and 1998: the title track (number 2), "It's Not Over" (number 34), "I Might Even Quit Lovin' You" (number 18), and "Wherever You Are" (number 45).  "Wherever You Are" was the first single of Chesnutt's career to miss the Top 40 on the country charts.  With this album, Chesnutt is also reunited with producer Mark Wright, who produced Chesnutt's first four MCA Nashville albums. "Thank God I Found You" is a song by American singer and songwriter Mariah Carey.  It features guest vocals from R&B singer Joe and American boy band 98 Degrees.  Written and produced by Carey along with Jimmy Jam and Terry Lewis, the song was released on January 25, 2000, through Columbia Records as the second single from her seventh studio album, "Rainbow" (1999).  "Thank God I Found You" is an R&B power ballad that was inspired by a relationship Carey was going through at the time, and lyrically recounts a powerful love relationship in which the protagonist tells her lover "thank God I found you." The Collection is the only compilation album released by the late 1990s teen pop boy band, 98 Degrees.  It was released on May 7, 2002.  The greatest hits album includes some songs from their old albums, and the smash Mariah Carey hit "Thank God I Found You", on which 98 Degrees collaborated with Joe alongside Carey. Let Them Be Little is the seventh studio album by American country music singer Billy Dean.  His first album since "Real Man" seven years previous, it is also his first release on Curb Records.  The album was originally to have been released in 2003 on View 2 Records, which promoted the first two singles ("I'm in Love with You" and a cover of John Denver's "Thank God I'm a Country Boy").  Asylum-Curb promoted the third single, "Let Them Be Little", which was co-written by Richie McDonald, lead singer of Lonestar, and recorded by the band on their 2004 album "Let's Be Us Again".  After this song came "This Is the Life", "Race You to the Bottom" and "Swinging for the Fence".  Also included on the album are re-recordings of "Somewhere in My Broken Heart" and "Billy the Kid", two of Dean's early singles from 1991 and 1992.
Answer: Billy Dean