Kitaigorodsky, A.
Foreign Language, [Date of publication not identified]
Buku Teks SO
Nave, Carl R.
W.B. Saunders, 1983
Buku Teks SO
Jensen, J. Trygve
John Wiley & Sons, 1982
Buku Teks SO
Seeger, Karlheinz
Springer-Verlag, 1989
Buku Teks SO
Burcham, W.E.
Longman , 1978
Buku Teks SO