edited by Wolfgang S. Homburger, Louis E. Keefer and William R. McGrath
Prentice-Hall, 1994
Buku Referensi
edited by C.A. O'Flaherty
Edward Arnold, 1997
Buku Teks
Artikel Jurnal
Currin, Thomas R., author
Brooks/Cole, 2001
Buku Teks
Salter, R.J.
Macmillan, 1983
Buku Teks