By Allenby, R. B. J. T.
By Strogatz, Steven
By Andrew Viner
By Dudeney, H.E.
By Chernyak, Yuri B., Rose, Robert M.
By Weinstein, Lawrence, Adam, John A.
By Norris, Hazel
By Sautoy, Marcus du, Marcus Du Sautoy
By The Times Mind Games
By Bounford, Trevor
By Rob Eastaway
By Cadwell, J. H.
By Shasha, Dennis E.
By Martin, Ray, IMGS, Inc., Estate of Rosser Reeves
By Julius, Edward H.
By Wells, David
By Straker, Anita
By Brian Bolt, Bolt, Brian
By Carol A Thornton
By Blum, Raymond, Sinclair, Jeff
By Buglear, John
By Mabey, Richard
By Alex Bellos, Ben Lyttleton, Spike Gerrell
By Hard Charlotte
By AIIA, Times Mind Games
By Julian Dismore
By Maisner H Rowe
By Peter Gordon, Frank Longo
By Collins KS1
By Martin Gardner