Horowitz, Irving Louis, author
Oxford University Press, 1972
Buku Teks
Hettne, Bjorn 1939-
Longman Scientific & Technical , 1995
Buku Teks
Olson, William Clinton, author
Prentice Hall International, 1994
Buku Teks
Schachter, Oscar, 1915-, author
Martinus Nijhoff , 1991
Buku Teks
Midgley, James, author
Sage, 2014
Buku Teks