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.
Power to the People (song) "Power to the People" is a song written by John Lennon, released as a single in 1971, credited to John Lennon/Plastic Ono Band. It was issued on Apple Records (catalogue number R5892 in the United Kingdom, 1830 in the United States) and in the US peaked at number 11 on the "Billboard" Hot 100 and number 10 on the "Cashbox" Top 100. It also charted at number 6 on the British singles chart. The song's first appearance on album was the 1975 compilation "Shaved Fish".