Reid, J.H. Stewart
Longman, Green, 1959
Buku Teks SO
Hutheesing, Raja
Orient Longman, 1960
Buku Teks SO
Hamilton, Mark
Neo-tech books, 2000
Buku Teks
National Committee for the Tenth Conference of Heads of State or Government of Non-Aligned Countries
Gramedia Pustaka Utama, 1992
Buku Teks SO
World Health Organization
World Health Organization, 1976
Buku Teks SO