Williams, James
Acumen, 2005
Buku Teks SO
Stein, Theodore J.
Columbia University Press, 2001
Buku Teks
edited and introduced by Andrew Shonfield and Stella Shaw
Heinemann Educational Books, 1972
Buku Teks
edited by Peter Dwyer, Sandra M I Shaw
Sage, 2013
Buku Teks
Cambridge University Press, 2018
Majalah, Jurnal, Buletin