Vanderveken, Daniel
Cambridge University Press, 1990
Buku Teks SO
Woolf, Virginia
Harcourt, Brace, 1941
Buku Teks SO
Jackson, Howard, 1945-
Longman, 1996
Buku Teks SO
Goddard, Harold C.
Phienix Books, 1990
Buku Teks SO
compiled by Herbert A. Simon
Prentice-Hall, 1972
Buku Teks SO