Question: What song does Ozzy refer to in his song "Dreamer"  that was written by John Lennon, that encourages a world at peace?

full_context: Document 1: How? (song): "How?" is a song from John Lennon's second solo album "Imagine", released in 1971. It is a contemplative song inspired by the Primal Therapy he was undergoing with his wife Yoko Ono, during which he faced many personal questions such as "How can I go forward when I don't know which way I'm facing?" This song also shows his thoughts about the world in general (such as "And the World is so tough; Sometimes I feel I've had enough").
Document 2: Down to Earth (Ozzy Osbourne album): Down to Earth is the eighth studio album by British heavy metal vocalist Ozzy Osbourne. Released on 16 October 2001, the album reached number 19 on the UK Albums Chart and number four on the US "Billboard" 200 albums chart. "Down to Earth" spawned just two singles, although both reached the top-ten of the US Hot Mainstream Rock Tracks chart and reached number 18 on the UK Singles Chart. The album was certified Platinum and has sold over 1.6 million copies worldwide.
Document 3: Give Peace a Chance: "Give Peace a Chance" is an anti-war song written by John Lennon (credited to Lennon–McCartney), and performed with Yoko Ono in Montreal, Quebec, Canada. Released as a single in 1969 by the Plastic Ono Band on Apple Records (catalogue Apple 13 in the United Kingdom, Apple 1809 in the United States), it is the first solo single issued by Lennon, released when he was still a member of the Beatles, and became an anthem of the American anti-war movement during the 1970s. It peaked at number 14 on the "Billboard" Hot 100 and number 2 on the British singles chart.
Document 4: The Dreamer (Blake Shelton album): The Dreamer is the second studio album released by American country music artist Blake Shelton. Released in 2003 on Warner Bros. Records Nashville, it features the Number One single "The Baby," as well as the singles "Heavy Liftin'" and "Playboys of the Southwestern World." "The Dreamer" is certified gold by the Recording Industry Association of America and features staff writers on all but one track.
Document 5: Dream This: Dream This is the debut album from Joe 90, released on Adam Duritz of Counting Crows's label E Pluribus Unum through Geffen. "Rolling Stone" said "singer-guitarist Chris Seefried steers along melodically facile, softly yelping rockers like 'Mascara' and 'Drive' - the album's showstopper - with velvety imprecision."
Document 6: No More Tears: No More Tears is the sixth studio album by British heavy metal vocalist and songwriter Ozzy Osbourne. Released on 17 September 1991, the album charted at number 17 on the UK Albums Chart and number seven on the US "Billboard" 200 albums chart. "No More Tears" spawned four songs which reached the top ten of the US Hot Mainstream Rock Tracks chart, including the number-two "Mama, I'm Coming Home", and it contains the Grammy-winning track "I Don't Want to Change the World". It is also one of Osbourne's two best-selling albums in North America, along with "Blizzard of Ozz", having been certified quadruple platinum by the RIAA and double platinum by CRIA. It was the last Ozzy Osbourne album to feature drummer Randy Castillo and bassist Bob Daisley.
Document 7: How Do You Sleep? (John Lennon song): "How Do You Sleep?" is a song by English musician John Lennon from his 1971 album "Imagine". The song makes angry and scathing remarks aimed at his former Beatles bandmate and songwriting partner, Paul McCartney. Lennon wrote the song in response to what he perceived as personal slights by McCartney on the latter's "Ram" album. The track includes a slide guitar solo played by George Harrison, also a former member of the Beatles.
Document 8: Ozzy Osbourne: John Michael "Ozzy" Osbourne (born 3 December 1948) is an English singer, songwriter, and actor. He rose to prominence in the early 1970s as the lead vocalist of the heavy metal band Black Sabbath. He was fired from Black Sabbath in 1979 and went on to have a successful solo career, releasing 11 studio albums, the first seven of which were all awarded multi-platinum certifications in the US. Osbourne has since reunited with Black Sabbath on several occasions, recording the album "13" in 2013. His longevity and success have earned him the informal title of "Godfather of Heavy Metal".
Document 9: Imagine (John Lennon song): "Imagine" is a song written and performed by English musician John Lennon. The best-selling single of his solo career, its lyrics encourage the listener to imagine a world at peace without the barriers of borders or the divisions of religion and nationality, and to consider the possibility that the whole of humanity would live unattached to material possessions.
Document 10: Imagine (John Lennon album): Imagine is the second studio album by John Lennon. Recorded and released in 1971, the album is more heavily produced in contrast to the basic, raw arrangements of his previous album, the critically acclaimed "John Lennon/Plastic Ono Band".
Document 11: I'm the Greatest: "I'm the Greatest" is a song written by English musician John Lennon that was released as the opening track of the 1973 album "Ringo" by Ringo Starr. With Starr, Lennon and George Harrison appearing on the track, it marks the only time that three former Beatles recorded together between the band's break-up in 1970 and Lennon's death in 1980. Lennon wrote the song in December 1970 as a wry comment on his rise to fame, and later tailored the composition for Starr to sing. Named after one of Muhammad Ali's catchphrases, the song partly evokes the stage-show concept of the Beatles' 1967 album "Sgt. Pepper's Lonely Hearts Club Band".
Document 12: Under Cover: Under Cover is the ninth studio album by heavy metal vocalist Ozzy Osbourne. The album consists entirely of cover songs. This is Osbourne's first and only album to feature cover songs from various artists, although in 1982, Osbourne had released the live album "Speak of the Devil" featuring renditions of songs from his time with Black Sabbath. All but 4 songs were originally released in the box set "Prince of Darkness", released earlier the same year. The additional songs on this album which are not featured in "Prince of Darkness" are "Rocky Mountain Way", "Sunshine of Your Love", "Woman" and "Go Now".
Document 13: Nowhere Man: The Final Days of John Lennon: Nowhere Man: The Final Days of John Lennon, first published in 2000 and written by New York journalist Robert Rosen, who in 1981 had access to John Lennon's diaries, is a controversial account of the ex-Beatle's last five years. The book disputes the official view of Lennon as a contented househusband raising his son Sean and baking bread while Yoko ran the family business. Instead, "Nowhere Man" portrays Lennon's daily life at the Dakota as that of a "tormented superstar, a prisoner of his fame, locked in his bedroom raving about Jesus Christ, while a retinue of servants tended to his every need."
Document 14: Dreamer (Ozzy Osbourne song): "Dreamer" is the third track from Ozzy Osbourne's album "Down to Earth", which was released on October 16, 2001. The single peaked at number 10 on "Billboard'"s Mainstream Rock Tracks. The song describes the rockstar's vision of a better world for his children, where they are happy and safe. In the liner notes to Osbourne's "Prince of Darkness" box set, Ozzy refers to this song as his version of John Lennon's "Imagine". A second video was also produced, featuring highlights from "The Osbournes". The Japanese and European press of the single also include a slightly different version of the song Dreamer, dubbed on the single "Dreamer (acoustic)", and a previously unreleased song titled "Black Skies".
Document 15: Imagine Peace Tower: The Imagine Peace Tower (Icelandic: "Friðarsúlan" , meaning "the peace column") is a memorial to John Lennon from his widow, Yoko Ono, located on Viðey Island in Kollafjörður Bay near Reykjavík, Iceland. It consists of a tall tower of light, projected from a white stone monument that has the words "Imagine Peace" carved into it in 24 languages. These words, and the name of the tower, are a reference to Lennon's campaign for peace, and his song "Imagine".
ground_truth: Imagine