Graham, Loren R., author
Cambridge University Press, 1993
Buku Teks
Suwarno, author
Bina Aksara, 1982
Buku Teks
Roberts, R.S., author
Elex Media Komputindo, 1981
Buku Referensi
Artikel Jurnal
Hinca IP Panjaitan ... [and others]
Internews Indonesia, 2000
Buku Teks