Tay, B. (2007). Biology InsightsO Level Theory WorkbookBeverly Tay ;consultant: Caroline Koh. Pearson Longman.
Lua i Stíl Chicago (17ú heag.)Tay, Beverly. Biology InsightsO Level Theory WorkbookBeverly Tay ;consultant: Caroline Koh. Pearson Longman, 2007.
Lua MLA (8ú heag.)Tay, Beverly. Biology InsightsO Level Theory WorkbookBeverly Tay ;consultant: Caroline Koh. Pearson Longman, 2007.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.