Seal, B. (1989). Vocabulary builder 2. Longman Group UK.
Lua i Stíl Chicago (17ú heag.)Seal, Bernard. Vocabulary Builder 2. Harlow Essex, England: Longman Group UK, 1989.
Lua MLA (9ú heag.)Seal, Bernard. Vocabulary Builder 2. Longman Group UK, 1989.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.