Giggins, L. W., & Shoebridge, D. J. (1970). Tense drills. Longman.
Lua i Stíl Chicago (17ú heag.)Giggins, L. W., agus D. J. Shoebridge. Tense Drills. Londres: Longman, 1970.
Lua MLA (9ú heag.)Giggins, L. W., agus D. J. Shoebridge. Tense Drills. Longman, 1970.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.