Useless Quotes
Scott Westerfeld (2009). “Bogus to Bubbly: An Insider's Guide to the World of Uglies”, p.116, Simon and Schuster
"In Praise of Idleness and Other Essays". Book by Bertrand Russell, Ch. 2: 'Useless' Knowledge, 1935.
Karl Marx, Friedrich Engels (1942). “Karl Marx and Frederick Engels: selected correspondence, 1846-1895: with explanatory notes”
P. J. O'Rourke (2007). “Give War a Chance: Eyewitness Accounts of Mankind's Struggle Against Tyranny, Injustice, and Alcohol-Free Beer”, p.22, Grove/Atlantic, Inc.
Theodore Levitt (1974). “Marketing for business growth”, McGraw-Hill Companies
Anton Szandor LaVey (2000). “The Devil's Notebook”, p.17, Feral House
"Éventuellement... (Possibly...)". Essay by Pierre Boulez (1952) published in his book "Stocktakings from an Apprenticeship" (p. 133), 1991.