Lyall, Francis, author
Routledge, 2018
Buku Teks
Hume, David
J.M. Dent & Sons , 1959
Buku Teks
edited by Walter S. Root and Frederick G. Hofmann
Academic Press, 1987
Buku Teks
Ehrenzweig, Albert A., author
West Publishing, 1962
Buku Teks
Lipsey, Richard G., 1928-, author
Harper Collin, 1996
Buku Teks