Gamble, Teri Kwal, author
Allyn and Bacon, 1994
Buku Teks
Park, Francis Y. T., author
Hollym International , 1984
Buku Teks
Luoma, Sari, author
Cambridge University Press, 2007
Buku Teks
Artikel Jurnal
by Cal M. Lague [and others]
Allyn and Bacon, 1982
Buku Teks