Weiss, Leonard W., author
John Wiley & Sons, 1981
Buku Teks
Feather, John, author
Facet Publishing, 2004
Buku Teks
Schraeder, Peter J., author
Thomson, 2004
Buku Teks
Lincoln, John A.
George Allen and Unwin, 1967
Buku Teks
Vavoulis
s.n., 1978
Buku Teks