What song does Ozzy refer to in his song "Dreamer"  that was written by John Lennon, that encourages a world at peace?
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.
John Lennon/Plastic Ono Band John Lennon/Plastic Ono Band is the debut studio album by English rock musician John Lennon. It was released in 1970, after Lennon had issued three experimental albums with Yoko Ono and "Live Peace in Toronto 1969", a live performance in Toronto credited to the Plastic Ono Band. The album was recorded simultaneously with Ono's debut avant garde solo album, "Yoko Ono/Plastic Ono Band", at Ascot Sound Studios and Abbey Road Studios using the same musicians and production team and nearly identical cover artwork.