Wheeler, Margaret
Hart Publishing Company, 1967
Buku Teks
Hooker, M. B.
Malaya Law Review, 1967
Buku Teks
Botsford, George Willis
Macmillan, 1939
Buku Teks
Farrington, Karen
Chancellor Pres, 1998
Buku Referensi
Russell B Gunia
USA : ASM International, 1977
Buku Teks