By Smethers, Michael
By Whitcomb, Alan
By N.G. Masson, F. Monaghan, L. Thompson
By Salters' Science Team, Aitkin, Mary, etc.
By Umeasiegbu, Remo Nna
By SPMG
By Dickens, Charles
By Abbott, A.F., Nelkon, Michael
By Scottish Primary Mathematics Group
By Abrahams, Peter
By Reynoldson, Fiona
By Vorderman, Carol, Hudson, Miles
By Shuter, Jane, Hook, Adam, Witherby
By Boyle, Trudy
By Berlitz Guides
By Reynoldson, Fiona, Shuter, Jane
By Roberts, Samantha
By Pye, Wendy
By egrest, Mab