Stevens & Sons, 1991
Buku Teks
Richard D. Irwin, 1972
Buku Teks
edited by Royall Brandis and Steven R. Cox
Richard D. Irwin, 1972
Buku Teks
Kelsen, Hans, author
Clarendon Press Oxford, 1992
Buku Teks
Hutchinson, E.P., author
American Association , 1949
Buku Teks