United Nations, 1992
Buku Referensi
Danadhyaksa Zulu Savano
Fakultas Hukum Universitas Indonesia, 2025
UI - Skripsi Membership
Mascull, Bill
Harper Collins Publishing, 1995
Buku Teks SO
Wanda Firmansyah [and others]
USAID, 2001
Buku Teks SO
Hartley, John
Cambridge University Press, 2006
Buku Teks SO