Martin, H.(2002).Advanced grammar in Use : A self-study reference and practice book for advanced learners of English with answers / Martin Hewings (Ed.ke-2, Cet.2).Jakarta:Erlangga.
Gaya MLA
Hewings, Martin."Advanced grammar in Use : A self-study reference and practice book for advanced learners of English with answers / Martin Hewings".Ed.ke-2, Cet.2Jakarta:Erlangga,2002.Skripsi.