Stuart J. Murphy. (2002). Double the Ducks (MathStart 1). HarperCollins.
Lua i Stíl Chicago (17ú heag.)Stuart J. Murphy. Double the Ducks (MathStart 1). HarperCollins, 2002.
Lua MLA (9ú heag.)Stuart J. Murphy. Double the Ducks (MathStart 1). HarperCollins, 2002.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.