By Roebuck, E., Sherlock, Alan, Godfrey, M., Pickles, J.
By Hefter, Richard
By Ticktock
By Cullerne, Dr. John
By Fannon, Paul, Ward, Stephen
By Kirkby, David
By Richardson, Peter
By Frank Tapson, Tapson, Frank
By Newman, Graham, Bull, Ron
By Julius, Edward H.
By Haslam, John
By Kent County Council
By School Mathematics Project
By Ellis, Jane, Poddington, Lucy, Pumpkin House
By Gardner, Ian
By Buckwell, G.D.
By Igloo Books
By Schofield & Sims, Steve Mills, Hilary Koll
By Bulloch, Ivan
By Collins GCSE
By Vorderman, Carol
By Vickers, K. M., Tipler, M. J.
By Norris, Roger
By Morris, JoAnne
By Kingscourt/McGraw-Hill