McLuskie, Kathleen E.
St. Martin's Press, 1994
Buku Teks SO
Ketton-Cremer, Robert Wyndham, 1906-
British Council by Longmans, Green, 1958
Buku Teks SO
Samuels, Charles E.
Twayne, 1965
Buku Teks SO
De Ford, Miriam Allen
Twayne Publishers, 1967
Buku Teks SO
Rae, Wesley D.
Twayne, 1967
Buku Teks SO