Pound, Roscoe, author
Wm.W. Gaunt and Sons, 1986
Buku Teks
Grob, Grald N.
The Free PRess,
Buku Teks
Mumford, Lewis, author
Brace Jovanovich, 1972
Buku Teks
Hurst, James Willard
Macmillan, 1964
Buku Teks
Robinson, O.F., author
Frofessional Books Limited, 1985
Buku Teks