edited Scott G. Mcnall
Little, Brown, 1968
Buku Teks SO
edited by Scott G. McNall
Little, Brown and Company, 1968
Buku Teks SO
Mueller, Gerhard G.
Richard D. Irwin, 1994
Buku Teks
Cox, Roger
Financial Times, Prentice-Hall, 2000
Buku Teks SO
Din, Rasshied
Conran Octopus, 2000
Buku Referensi