edited by Harold B. Allen
McGraw-Hill, 1965
Buku Teks
Allen, Edward D.
Harcourt Brace Jovanovich, [Date of publication not identified]
Buku Teks
Stevick, Earl W.
Abingdon, 1967
Buku Teks
Morris, I.
Macmillan and Co. Ltd., 1950
Buku Teks
Byrd, Patricia
Prentice-Hall, 1981
Buku Referensi