Underwood Dudley, Gerald L. Alexanderson, Nathan Altshiller-Court, John Aubry, Girolamo Cardano (2008). “Is mathematics inevitable?: a miscellany”, The Mathematical Association of America
Henry David Thoreau, Jeffrey S. Cramer (2007). “I to Myself: An Annotated Selection from the Journal of Henry D. Thoreau”, p.201, Yale University Press