Longman Community Information
Longman Grup, 1994
Buku Referensi
Asia Law & Practice, 2004
Buku Teks
edited by Janice McLean
Gale Research, 1991
Buku Referensi
Stein, Lincoln D., author
Wiley, 1998
Buku Teks
Langer, Maria, author
Osborne/McGraw-Hill, 1999
Buku Referensi