By Bailie, J.M.
By Prefontaine, M
By Parkinson, Judy
By Moscovich, Ivan
By Deslandes, Clement, Guillaume
By NO AUTHOR
By The guardian
By Vaughan, Johnny, Outen, Denise van
By Moore, Dr Gareth
By Smullyan, Raymond M.
By You, Have I Got News For
By Tulloch, Alexander
By Barry R. Clarke, illustrated by Rob Collinet
By Kampelmann
By Arcturus Publishing
By Schott, Ben
By Bradford, Anne R., Collins Puzzles
By Wyse, Elizabeth, Anon
By Bellos, Alex
By Somerville, Neil
By The Times Mind Games, .
By Standage, Tom
By Ayto, John
By The Times Mind Games
By Tarbuck, Liza
By Lange, Catherine De
By The UK Mathematics Trust