By ALISON JEFFERSON
By Cundy, H.M., Rollett, A.R.
By Gibbs, WILLIAM
By Diyan Leake
By Jordan, David
By Maxwell, Sadie
By Nash, Jenny
By Worden, Jan
By School Mathematics Project
By Kirkby, David
By McDougal Littel
By Kirkby, Dave, DavidM, Ruth Merttens, Dave Kirkby
By Hirst, Keith
By Lowndes, Sue, D'Angelo, Simon, Jeffrey, Andrew, Gibbs, Elizabeth
By Jeffrey, Andrew
By Johnston-Wilder, Sue, Mason, John
By Kirkby, DavidM, Ruth Merttens, David Kirkby
By Brodie, Andrew
By Brodie, Andrew, Andrew Brodie
By Schofield & Sims, Steve Mills, Hilary Koll
By Heylings, M. R.