Johnson, Paul, author
Weidenfeld and Nicolson, 1983
Buku Teks
edited by G. Goodwin
Cambridge University Press, 1958
Buku Teks
Palmer, R.R. (Robert Roswell), 1909-2002, author
McGraw-Hill, 1992
Buku Teks
Cambridge University Press, 1965
Buku Teks
Mayer, Frederick, author
American Book Company, 1951
Buku Klasik