Bauer, Laurie
Cambridge Cambridge University Press 1983
Buku Teks
England Longman 1983
Buku Referensi
Beijing Waiyanshe (Foreign Language Teaching and Research Press) 2001
Buku Referensi
New York Funk and Wagnalls 1958
Buku Referensi
Stratmann, Francus Henry
London Oxford University Press 1958
Buku Referensi