J. Anthony Bristow, editor
John Wiley & Sons, 1997
Buku Referensi
edited by Christopher Morris
Academic Press, 1992
Buku Referensi
Keller, Edward A., author
John Wiley & Sons, 2014
eBooks
Dorian, A.F., author
Elsevier Scientific Publishing Company, 1981
Buku Referensi
United Nations , 1963
Buku Teks