Wilson, Billie Ann, author
Prentice-Hall, 2003
Buku Referensi
Benyamin Molan, author
Prenhallindo, 2002
Buku Referensi
Katzner, Kenneth, author
Routledge, 1995
Buku Referensi
Peter Lang International Academic Publishin Group, 2010
Majalah, Jurnal, Buletin
edited by Diane Brentari
Cambridge University Press, 2010
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