Outhwaite, William
Blackwell, 2006
Buku Teks
Eagleton, Clyde
New York University press, 1945
Buku Teks
Doorn, Jacques van
Faculty of Social Sciences, Erasmus University Rotterdam, 1983
Buku Teks
McNeill, Patrick
Macmillan, 1991
Buku Teks
edited by Clark Tibbitts and Wilma Donahue
Prentice-Hall, 1960
Buku Teks