edited by C.A. O'Flaherty
Edward Arnold, 1997
Buku Teks
Garber, Nicholas J.
PWS Publishing, 1996
Buku Teks
edited by Wolfgang S. Homburger, Louis E. Keefer and William R. McGrath
Prentice-Hall, 1994
Buku Referensi
Martine, Roberta R.
Prentice-Hall, 1994
Buku Teks
Hobbs, F.D.
Pergamon Press, 1974
Buku Teks