Breul, Karl, author
Boston D.C. Heath 1936
Buku Referensi
Stratmann, Francus Henry
London Oxford University Press 1958
Buku Referensi
Fowler, H. W. (Henry Watson), 1858-1933, author
New York Oxford University Press 1965
Buku Referensi
England Longman 1983
Buku Referensi
editor, John DeFrancis
Allen & Unwin, 1997
Buku Referensi