MacDonald, Ian (2002). “The Psychedelic Experience”. Mojo Special Limited Edition: 1000 Days That Shook the World (The Psychedelic Beatles – April 1, 1965 to December 26, 1967). London: Emap. p. 34. "Lennon is the main author of nearly all of The Beatles' psychedelic classics: Tomorrow Never Knows, I'm Only Sleeping, Rain, She Said She Said ... I Am the Walrus, Across the Universe."