By M. Remoissenet
By C.W. CELIA, etc., A. T. F. Nice, K. F. Elliott
By Rufus P. Turner
By Thornton, Linvill, Chenette, Ablin, Harris, Boothroyd, Willis, Searle
By Towers, David A.
By Leonard Saunders, Robert Fleming
By Robin Scagell, David Frydman
By Patrick Moore
By Geoffry Matthews
By C. A. R. Bailey
By G. Matthews
By A. E. Coulson
By Various Authors
By Porter, R.I.
By R. L. Bolt
By Raymond W Anderson
By Derek Holton
By Derek Allan Holton
By W L Ferrar
By Hunter, John, Scottish Mathematics Group, Monk, David
By Hugh Neill
By D. A. Young
By C. V. Durell
By Paulos John Allen
By Canadian Mathematics Competition
By J. A. C. Reynolds
By PM cohn