Hoover, Kenneth R., 1940-, author
Thomson, 2008
Buku Teks
Wilson, E. Bright, author
McGraw-Hill, 1952
Buku Teks
Engels, F. E.
Foreign Languages Publishing House, 1958
Buku Teks
Boyle, Mary, author
Taylor and Francis, 2002
Buku Teks
Barradas, Gerald
Pageant Press , 1956
Buku Teks