Gaya APA

Walford, A., Whitehead, R. (2011). Edexcel IGCSE English as a Second Language: Practice Tests Reading and Writing . Cambridge: Cambridge University Press.

Gaya MLA

Walford, Alison., Whitehead, Russell. "Edexcel IGCSE English as a Second Language: Practice Tests Reading and Writing". Cambridge: Cambridge University Press, 2011. Buku Tercetak.