United States Information Agency, 1987
Buku Teks
Board of Trusless, 1960
Buku Referensi
Stuart, Graham H. (Graham Henry), 1887-, author
Appleton-Century-Crofts, 1955
Buku Teks
Whitaker,Arthur P.
Harvard University Press, 1948
Buku Teks
The America University, [date of publication not identified]
Buku Teks
Corwin, Edward S., author
U.S. Government Printing Office, 1953
Buku Teks