edited by Frances Farmer
Oceana, 1956
Buku Teks
Vinacke, Harold M.
Indiana University Press, 1957
Buku Teks
Hoover, Herbert, 1874-1964
McGraw-Hill, 1958
Buku Teks
Gruhn, Ruth
Pacatello, 1961
Buku Teks
Wilson, Woodrow
Columbia University, [date of publication not identified]
Buku Teks