David Singmaster, The Utility of Recreational Mathematics, in Richard K. Guy e Robert E. Woodrow (a cura di), The Lighter Side of Mathematics: Proceedings of the Eugène Strens Memorial Conference on Recreational Mathematics and Its History, Cambridge University Press, 1994, p. 340, ISBN0-88385-516-X. Singmaster estimates the numbers sold were between 100 and 300 million. His estimate is based on sales of 50 to 100 million legitimate cubes and perhaps a higher number of imitations.
David Singmaster, The Utility of Recreational Mathematics, in Richard K. Guy e Robert E. Woodrow (a cura di), The Lighter Side of Mathematics: Proceedings of the Eugène Strens Memorial Conference on Recreational Mathematics and Its History, Cambridge University Press, 1994, p. 340, ISBN0-88385-516-X.
Erica Noonan, Let's twist again, in The Boston Globe, 8 novembre 2003.
cube20.org
David Singmaster, The Utility of Recreational Mathematics, in Richard K. Guy e Robert E. Woodrow (a cura di), The Lighter Side of Mathematics: Proceedings of the Eugène Strens Memorial Conference on Recreational Mathematics and Its History, Cambridge University Press, 1994, p. 340, ISBN0-88385-516-X. Singmaster estimates the numbers sold were between 100 and 300 million. His estimate is based on sales of 50 to 100 million legitimate cubes and perhaps a higher number of imitations.
Henry Allen, The Cube, in The Washington Post, 10 giugno 1981.
web.archive.org
Michael Shanks, History of the Cube, su documents.stanford.edu, Stanford University, 8 maggio 2005. URL consultato il 26 luglio 2012 (archiviato dall'url originale il 20 gennaio 2013).
William Lee Adams, The Rubik's Cube: A Puzzling Success, in TIME, 28 gennaio 2009. URL consultato il 5 febbraio 2009 (archiviato dall'url originale il 1º febbraio 2009).
The History of Rubik's Cube - Erno Rubik, su inventors.about.com, 9 aprile 2012. URL consultato il 20 giugno 2012 (archiviato dall'url originale il 23 maggio 2020).
D. Kunkle e C. Cooperman, Twenty-Six Moves Suffice for Rubik's Cube (PDF), in Proceedings of the International Symposium on Symbolic and Algebraic Computation (ISSAC '07), ACM Press, 2007. URL consultato il 5 giugno 2008 (archiviato dall'url originale il 18 febbraio 2019).
Julie J. Rehmeyer, Cracking the Cube, su blog.sciencenews.org, MathTrek. URL consultato il 9 agosto 2007 (archiviato dall'url originale l'11 ottobre 2007).
(EN) Tomas Rokicki, Twenty-Two Moves Suffice for Rubik’s Cube (PDF), in The mathematical intelligencer, Volume 32, Number 1, Springer Science+Business Media, LLC, 2010. URL consultato il 21 maggio 2024 (archiviato dall'url originale il 4 giugno 2018).