Rosenthal, Marilyn S., author
Longman Inc., 1987
Buku Referensi
Pearson Education Limited, 2010
Buku Referensi
editor, Jean-Claude Corbeil
Macmillan Publishing Company, 1992
Buku Referensi
Oxford University Press, 1998
Buku Referensi
Pollmann, Friedrich, author
Macmillan, 1976
Buku Referensi