Fennell, F. (1991). Mathematics unlimited. Harcourt.
Lua i Stíl Chicago (17ú heag.)Fennell, Francis. Mathematics Unlimited. Orlando: Harcourt, 1991.
Lua MLA (9ú heag.)Fennell, Francis. Mathematics Unlimited. Harcourt, 1991.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.