Learned, Edmund P. (Edmund Philip), 1900-1991
Harvard University Press, 1951
Buku Teks
Learned, Edmund P. (Edmund Philip), 1900-1991
Andover Press, 1957
Buku Teks
Bernstein, Marver H.
The Brookings Institution, 1958
Buku Teks
Miles, Robert H
Sage Publications, 1983
Buku Teks
Maule, Frances
Harper & Brother , 1957
Buku Teks