Bennet, Tony
Routledge, 1997
Buku Teks SO
Bennett, Tony
Routledge, 1995
Buku Teks SO
Kitzinger, Sheila, 1929-
Elsevier, 2005
Buku Teks SO
edited by Andrea Cappelli, Elena Castellani, Filippo Colomo, and Paolo di Vecchia
Cambridge University Press, 2012
Buku Teks SO
Reynolds, Charles
Martin Robertson, 1973
Buku Teks SO