Jackson, R.M. (Richard Meredith), 1903-1986, author
Macmillan, 1959
Buku Teks
Cox, George, author
Thomson Learning, 2001
Buku Teks
Elcock, Howard, author
Routledge, 1994
Buku Teks
Bator, Francis M.
Harper , 1960
Buku Teks
Heilbroner, Robert L., author
Vintage Books , 1963
Buku Teks