Astuti, S. I. (2009). Simple step to toefl. Hi-fest Publishing.
Lua i Stíl Chicago (17ú heag.)Astuti, Santi Indra. Simple Step to Toefl. Hi-fest Publishing, 2009.
Lua MLA (8ú heag.)Astuti, Santi Indra. Simple Step to Toefl. Hi-fest Publishing, 2009.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.