Blackshaw, Carole
Pitman, 1992
Buku Teks
Speciale, Raymond C., author
McGraw-Hill, 2006
Buku Teks
Y. Sari Budiarti, author
Fakultas Hukum Universitas Indonesia, 2001
UI - Skripsi Membership
Cambridge University Press, 2018
eBooks
Pearson, Michael W., author
Pearson education, 2015
Buku Teks