Robertson, Brian J., author
Henry Holt and Company, 2015
Buku Teks
Paul, Richard W., author
Hawker Brownlow Education, 1993
Buku Teks
Dahrendorf, Ralf, author
Stanford University Press, 1975
Buku Teks
Wallerstein, Immanuel, author
Cambridge University Press, 1991
Buku Teks
Habbel, Rolf W., author
Palgrave Macmillan, 2002
Buku Teks