By Judita Cofman (Professor, Mathematics Institute, Professor, University of Erlangen)
By J.R. Irwin
By D. Rayner
By Fiona C Mapp
By Paul Broadbent, Peter Patilla
By David Green, Peter Armstrong, Richard Bridges, The Mathematical Association
By Letts A-level
By Parsons, Richard
By Rose Griffiths
By Wilbert Reimer, Luetta Reimer
By Wilbert Reimer
By richard-parsons, CGP Books
By Peter Robson
By Michael Haese, Sandra Haese, Robert Haese, James Foley, Alison Ryan
By Jim Haskins
By Oram, Hiawyn, Schon, Nick, Collins Big Cat, Moon, Cliff
By David Kirkby
By Colin Goldsmith, David Nelson, School Mathematics Project
By School Mathematics Project
By David Rayner
By Caroline Bucknall
By John Wood, Rosemary Emanuel, Janet Crawshaw
By Andrew Brodie
By Gill Potter, Cherri Moseley
By Karen Bryant-Mole, Zul Mukhida
By Hilary Koll, Steve Mills
By Gareth Cole, Tbc, Heather Davis, Sophie Goldie, Linda Liggett