Hill, L.A.
Word power 1500 : vocabulary tests and exercises in American English
Oxford University Press, 1982
Buku Teks SO
Dixson, Robert J.
Modern American English; Book 1
Regents Publishing, 1971
Buku Teks SO
Mastering American English: with recorded exercises for intermediate and advanced students / editor, Grant Taylor
McGraw-Hill, 1956
Buku Teks SO
Low, Ona
Proficiency in english course
Edward Arnold, 1986
Buku Teks SO
Alexander, L.G.
Fluency in English : an integrated course for advanced students
Longman, 1967
Buku Teks SO