Iddon, Ron
Australian Broadcasting Commision, 1974
Buku Teks
Weber, Ron
McGraw-Hill International Book Company, 1982
Buku Teks
Selby, Keith
MacMillan Press , 1995
Buku Teks
White, Ron, author
Prentice Hall International English Language Teaching , 1994
Buku Teks
Ali Aufa Fakhri, author
2018
UI - Skripsi (Membership)