Cross, Rod
Martin Robertson , 1982
Buku Teks
Andrerson, James E.
Addison-Wesley, 1970
Buku Teks
Artis, M.J.
Department of Economics, University of Manchester, [date of publication not identified]
Buku Teks
Spero, Joan Edelman
Wadsworth, 2010
Buku Teks
Spero, Joan Edelman
Routledge, 1994
Buku Teks