Molineu, Harold
Westview Press, 1990
Buku Teks
Hayes, Margaret Daly
Westview Press, 1984
Buku Teks
Hirschman, Albert O.
Twentieth Century Fund, 1963
Buku Teks
Teichert, Pedro C.M.
Bureau of Business Research Mississippi University , 1959
Buku Teks
edited by Eduardo P. Archetti
MacMillan Education, 1987
Buku Teks