By Various
By CGP Books
By Caroline Paechter
By David Smart
By Janet Wilson
By Ian Cassells, Mary Kay
By SQA
By Rosemary Emanuel, John Wood
By E. A. Bester, J. Ham, K. Loots, A. Stark
By Fairhurst, J.S.
By School Mathematics Project
By Ray Allan
By Paul Hambleton
By Vivian Lucas
By Jill Whieldon
By Tracey MacDonald
By Ralph Riddiough, Deanne Thomas
By Peter Patilla, Paul Broadbent
By K. M. Vickers, etc., M. J. Tipler, H.L. Van Hiele
By Letts GCSE, Fiona Mapp, Collins GCSE
By Prof. Alan Smith, Sophie Goldie
By Ric Pimentel, Terry Wall
By Peter Williams