Kaplan, Jeffrey P.
Prentice Hall International, 1995
Buku Teks
Jespersen, Otto
George Allen and Unwin, 1933
Buku Teks
Makkink, H.J.
Nijgh and Van Ditmar, 1951
Buku Teks
House, C. Homer
Prentice-Hall, 1950
Buku Teks
Geddes & Grosset, 2003
Buku Referensi