Evans, Desmond W.
Improving english skills
Pitman, 1989
Buku Teks SO
Langan, John, 1942-
English skills with readings
McGraw-Hill, 1991
Buku Teks SO
Koneru, Aruna
English language skills
Tata McGraw-Hill, 2011
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Scope english : writing and language skills level two
Scholastic, 1987
Buku Teks SO
Jordan, R. R.
Academic writing course : study skills in english
Longman, 2001
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