edited by W.L. Gibson, Jr, R.J. Hildreth, Gene Wunderlich
University of Nebraska Press, 1966
Buku Teks
editor, Robert Dorfman
Brooking Institution, 1965
Buku Teks
Chase, Samuel B., Jr., author
Brooking Institution, 1968
Buku Teks
Salter, Leonard A., author
University of Wisconsin Press, 1967
Buku Teks
Clawson, Marion
Gordon and Breach , 1972
Buku Teks