Clarke, L. H., & Norton, F. G. J. (1984). Ordinary Level mathematics (7th ed.(revised).). Heinemann Educational.
Lua i Stíl Chicago (17ú heag.)Clarke, L. Harwood, agus F. G. J. Norton. Ordinary Level Mathematics. 7th ed.(revised). London: Heinemann Educational, 1984.
Lua MLA (8ú heag.)Clarke, L. Harwood, agus F. G. J. Norton. Ordinary Level Mathematics. 7th ed.(revised). Heinemann Educational, 1984.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.