Borovik 2006, pp. 8–9, §5. How to draw an icosahedron on a blackboard. Borovik, Alexandre (2006). "Coxeter Theory: The Cognitive Aspects". In Davis, Chandler; Ellers, Erich (eds.). The Coxeter Legacy. Providence, Rhode Island: American Mathematical Society. pp. 17–43. ISBN978-0821837221.
Simmons 2007, p. 50. Simmons, George F. (2007). Calculus Gems: Brief Lives and Memorable Mathematics. Mathematical Association of America. ISBN9780883855614.