Smith, E. (1987). Examples in mathematics for GCSE: Higher level. Stanley Thornes.
Lua i Stíl Chicago (17ú heag.)Smith, Ewart. Examples in Mathematics for GCSE: Higher Level. Cheltenhorn, England: Stanley Thornes, 1987.
Lua MLA (9ú heag.)Smith, Ewart. Examples in Mathematics for GCSE: Higher Level. Stanley Thornes, 1987.
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