Holschuh, Louis W.
New York St. Martin's Press 1991,
Buku Teks
Longman Group UK Limited , 1975
Buku Teks
Harahap, P.R.
Jakarta Praninta Aksara [date of publication not identified],
Buku Teks
Marchant, James Robert Vernam, 1853-1936, editor
New York Funk & Wagnalls [t.th.]
Buku Teks
Janos, author
Budapest Franklin 1902
Buku Referensi