Prentice-Hall, 1960
Buku Teks
Cowen, Zelman
Oxford University Press, 1959
Buku Teks
edited by Bertus De Villiers
Martinus Nijhoff, 1994
Buku Teks SO
Wheare, K. C.
Oxford University Press, 1963
Buku Teks
McWhinney, Edward
A.W. Sijthoff, 1966
Buku Teks SO