Samuel, Charles E., editor
Springer, 2012
eBooks
Craig, Richard, author
Thomson/Wadsworth, 2005
Buku Teks
Williams, Herbert Lee
The Iowa State University Press, 1978
Buku Teks
Carr, Harry, author
Houghton Miffiln, 1934
Buku Teks
Mencken, H. L.
Alfred A. Knopf, 1963
Buku Teks