Oakley, C. O.; Wisner, R. J. (March 1957). "Flexagons". The American Mathematical Monthly. 64 (3). Mathematical Association of America: 143–154. doi:10.2307/2310544. JSTOR2310544.
Rogers, Russell E.; Andrea, Leonard D. L. (April 21, 1959). "Changeable amusement devices and the like"(PDF). Freepatentsonline.com. U.S. Patent 2883195. Archived(PDF) from the original on June 14, 2011. Retrieved January 13, 2011.
jstor.org
Oakley, C. O.; Wisner, R. J. (March 1957). "Flexagons". The American Mathematical Monthly. 64 (3). Mathematical Association of America: 143–154. doi:10.2307/2310544. JSTOR2310544.
Rogers, Russell E.; Andrea, Leonard D. L. (April 21, 1959). "Changeable amusement devices and the like"(PDF). Freepatentsonline.com. U.S. Patent 2883195. Archived(PDF) from the original on June 14, 2011. Retrieved January 13, 2011.