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
eBooks
edited by Diane Brentari
Cambridge University Press, 2010
Buku Teks
Tucker, Allen B., author
McGraw-Hill, 1986
Buku Teks