Albert Einstein (2015). “Bite-Size Einstein: Quotations on Just About Everything from the Greatest Mind of the Twentieth Century”, p.32, St. Martin's Press
David Icke (2003). “Tales from the Time Loop: The Most Comprehensive Exposé of the Global Conspiracy Ever Written and All You Need to Know to Be Truly Free”, David Icke Books
The Marriage of Heaven and Hell "A Memorable Fancy" plate 14 (1790 - 1793). Inspired the title of Aldous Huxley's 1954 book about drug experimentation, The Doors of Perception, which in turn inspired the name of the 1960s rock group The Doors.