By A. W. F. Edwards, Ian Stewart
By Collins Puzzles
By Petzold, Charles
By Deslandes, Clement, Guillaume
By Chaudhuri, Swarat, Farzan, Azadeh
By Suppes, Patrick
By DAN CRYAN, SHARRON SHATIL, BILL MAYBLIN, Mayblin, Bill, Cryan, Dan, Shatil, Sharron
By Chaitin, Gregory J.
By Maker, Brainstorm
By Lakatos/Worrall/Zahar
By William Bolton (Formerly Lecturer, Buckingham Chilterns University College, High Wycombe, UK)
By Peter J. Eccles (University of Manchester)
By Ralf Schindler
By Claude Sabbah
By Alexander Prestel, Charles N. Delzell
By Dirk van Dalen
By D.L. Johnson
By Ian M. Chiswell
By T.S. Blyth
By Mark Kac
By Rob Eastaway
By Stephen Hawking
By Marcus Du Sautoy
By W.H. Newton-Smith
By Douglas Jacobson
By Cummings, Jay
By AIIA, Times Mind Games
By Letts KS2
By Bangs Tapscott
By Andrew King