Its The teaching of trigonometry in schools, 1950.

Maths talk, 1990: CIP t.p. (Mathematical Association (U.K.))

OCLC 1585913: The Mathematical gazette, 1894- (official organ of the Mathematical Association; continues: Association for the Improvement of Geometrical Teaching (Great Britain). Report)

Its website, viewed 21 June 2016: home p. (Mathematical Association; MA; 259 London Road, Leicester, LE2 3BE; supporting mathematics in education) history p. (the MA was the first teachers' subject association to be formed in England, in 1871, as the 'Association for the Improvement of Geometrical Teaching', the original catalyst being the need to develop and to lobby for alternatives to the then standard treatment of geometry) membership p. (welcomes everyone with an interest in, and enthusiasm for, mathematics including teachers, inspectors and students)

Mathematical gazette, Feb. 1898: t.p. (Mathematical Association) ; Oct. 1895: t.p. verso (Association for the Improvement of Geometrical Teaching)

Index to the Mathematical Gazette, volumes 1-25, April 1894 to December 1931, 1933: p.ix (though it was not till 1897 that the Association for the Improvement of Geometrical Teaching, founded in 1871, changed its name to the Mathematical Association, it had already in 1881 widened its basis so as to include all branches of elementary mathematics and mathematical physics)