Davies, Stephen, 1950-
Wiley Blackwell, 2016
Buku Teks SO
Eldridge, Richard
Cambridge, 2003
Buku Teks
Hauser, Arnold
Routledge & Kegan Paul, 1959
Buku Teks
Jill Kraye and M. W. F. Stone
Routledge, 2000
Buku Teks
Tidman, Paul
Wadsworth, 1999
Buku Teks