United Nations Educational, Scientific and Cultural Organization (UNESCO)
UNESCO, 1984
Buku Teks
editor, Frank N. Magill
Salem Press, 1994
Buku Referensi
Thompson, James D., author
Transaction Publishers, 2003
Buku Teks
World Health Organization
WHO, 2005
Buku Teks
Williams, Malcolm, 1953-, author
Routledge, 2000
Buku Teks