Holschuh, Louis W.
The functions of the English grammer/Louis W. Holscchuh
New York St. Martin's Press 1991,
 Buku Teks
English grammatical structure : a general syllabus for teachers / L.G. Alexander...[et al.]
Longman Group UK Limited , 1975
 Buku Teks
Harahap, P.R.
English for banking/P. R. Harahap, editor khusus Harace H. Rice
Jakarta Praninta Aksara [date of publication not identified],
 Buku Teks
Klatt, Edmund
Langenscheidts Schulworterbuch English-Deutch; Deutsch English
Berlin Langenscheidt KG. Verlag buchhandlung 1961
 Buku Referensi
Bellow's German dictionary German - English, English - German
London, London Longmans
 Buku Referensi