Boies, David
Little,Brown and Company, 1977
Buku Teks
Irving, W Washington
Boston [etc.] Houghton Mifflin [1922]
Buku Teks
Redmond, Peter W.D.
The M & E Handbook Series, 1993
Buku Teks
Boies, David.
Little, Brown, 1977
Buku Teks
Leal, A.L.
Longman, 1978
Buku Teks