Farrar, John H., author
Sweet and Maxwell, 1977
Buku Teks
Berch, Michael A., author
West, 2010
Buku Teks
Gutteridge, H. C.
Cambridge University Press, 1949
Buku Teks
Bishin, William
Foundation Press, 1972
Buku Teks
Wesley-Smith, Peter, author
Oxford University Press, 1987
Buku Teks