John Locke, Ruth Weissbourd Grant, Nathan Tarcov (1996). “Some Thoughts Concerning Education: And, Of the Conduct of the Understanding”, Hackett Publishing
Scott Adams (2007). “Stick to Drawing Comics, Monkey Brain!: Cartoonist Explains Cloning, Blouse Monsters, Voting Machines, Romance, Monkey G ods, How to Avoid Being Mistaken for a Rodent, and More”, p.164, Penguin