Etherington, John R.
Wiley Eastern, 1976
Buku Teks SO
Etherington, John R.
John Wiley & Sons, 1982
Buku Teks SO
Silvertown, Jonathan W.
Longman, 1987
Buku Teks SO
Barbour, Michael G.
Benjamin/Cummings, 1987
Buku Teks SO
edited by J.R. Porter and D.W. Lawlor
Cambridge University Press, 1991
Buku Teks SO