1. Zito, R. R. (2011, August 8–12). The Curious Bent Pin problem—I: Computer search methods. In 29th International Systems Safety Conference, Las Vegas, NV.
2. Zito, R. R. (2011, August 8–12). The Curious Bent Pin problem—II: Matrix methods. In 29th International Systems Safety Conference, Las Vegas, NV.
3. Campbell, J. (1990). Transformations of myth through time (pp. 164–184). New York: Harper & Row.
4. Adkinson, R. (Ed.). (1995). Sacred symbols (p. 183). New York: Abrams.
5. Ouaknin, M. A. (2010). Mysteres des Chiffres (pp. 289–294). Paris: Assouline.