Robbins, Sydney M.
Houghton Miffiln, 1954
Buku Teks
Cooley, Thomas M.
Little, Brown and Company, 1898
Buku Teks
Noll, Edward M.
Howard W. Sams, , 1978
Buku Teks
Murphy, Regina M.
McGraw-Hill, 2007
Buku Teks
Ozsu, M. Tamer, author
Prentice-Hall, 1991
Buku Referensi