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