Helsop, A. (1999). Ageing and Development.
Lua i Stíl Chicago (17ú heag.)Helsop, Amanda. Ageing and Development. 1999.
Lua MLA (8ú heag.)Helsop, Amanda. Ageing and Development. 1999.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.