Athitakis, Mark (September–October 2013). “A Beatles Reflection”. Humanities (National Endowment of the Humanities) 34 (5). http://www.neh.gov/humanities/2013/septemberoctober/statement/beatles-reflection. "The Beatles, by contrast, was scruffy and centerless, its thirty songs encompassing mock-Beach Boys vocal harmonies ('Back in the U.S.S.R.'), ... proto-punk ('Helter Skelter'), sound collage ('Revolution 9'), and plenty more besides."
“Notes on 'Revolution #9'”. Soundscapes.info. 2021年11月1日閲覧。 “As one of the more infamous achievements of the mid twentieth century avant garde, this form of musical composition challenges the listener on both psychological and philosophical grounds.”